Experimental Research Concepts Quiz
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Questions and Answers

What is the primary purpose of manipulation in experimental research?

  • To increase the sample size
  • To eliminate all variables
  • To determine the direction of the effect (correct)
  • To create a control group

    • Which of the following is NOT one of the basic elements unique to experimental research?

  • Manipulation
  • Comparison
  • Measurement
  • Random Sampling (correct)

    • In an experiment examining the effect of TV violence on aggression, which variable is the independent variable (IV)?

  • Time spent watching TV
  • Aggression
  • Viewer's age
  • TV violence (correct)

    • What does controlling other variables in an experiment aim to achieve?

    <p>Support the validity of the experiment</p> Signup and view all the answers

    Which scenario best illustrates the concept of manipulation in an experiment?

    <p>Varying the amount of Prozac administered to patients</p> Signup and view all the answers

    What assumption is made in experimental research regarding the relationship between the independent variable (IV) and dependent variable (DV)?

    <p>The researcher has controlled for all other variables</p> Signup and view all the answers

    In the context of the Third Variable Problem, what role does manipulation serve?

    <p>To control the influence of outside variables</p> Signup and view all the answers

    Which of the following is an example of how manipulation can determine the direction of an effect?

    <p>Increasing ice cream consumption leads to higher crime rates</p> Signup and view all the answers

    What is the role of the researcher in manipulating the independent variable (IV)?

    <p>To ensure the IV changes without external influence</p> Signup and view all the answers

    Why is it important to control for extraneous variables in an experiment?

    <p>They may correlate with the DV, falsely suggesting a relationship</p> Signup and view all the answers

    What defines a confounding variable in an experimental study?

    <p>A variable that changes systematically with the IV and can influence the DV</p> Signup and view all the answers

    Which of the following statements about confounding variables is correct?

    <p>They provide alternative explanations for results when related to the IV</p> Signup and view all the answers

    What should be ensured when manipulating the independent variable in a study?

    <p>No third variables impact the relationship being studied</p> Signup and view all the answers

    What is the primary distinction between extraneous and confounding variables?

    <p>Confounding variables vary systematically with the IV, but extraneous ones do not</p> Signup and view all the answers

    Why must the researcher eliminate confounding variables in an experiment?

    <p>To accurately assess cause and effect relationships</p> Signup and view all the answers

    Which of the following is an example of an extraneous variable?

    <p>Age of participants in a study on stress and performance</p> Signup and view all the answers

    What is the primary hypothesis tested in the sweetened cereals example?

    <p>Sweetened cereals are preferred over unsweetened cereals.</p> Signup and view all the answers

    In the music lesson example, what is the independent variable (IV)?

    <p>Exposure to music lessons.</p> Signup and view all the answers

    How is a confounding variable defined in the context of the memory experiment with background music?

    <p>A variable that only impacts one of the experimental conditions.</p> Signup and view all the answers

    What role does an extraneous variable play in an experiment?

    <p>It is a variable that can affect the dependent variable but is controlled across conditions.</p> Signup and view all the answers

    What potential issue does a confounding variable pose to internal validity?

    <p>It complicates the interpretation of whether the IV or CV caused changes in the DV.</p> Signup and view all the answers

    What distinguishes a controlled variable from a confounding variable in an experiment?

    <p>Controlled variables are held constant across conditions; confounding variables are uncontrolled.</p> Signup and view all the answers

    Which of the following scenarios illustrates a confounding variable?

    <p>One group has higher noise levels than another during testing.</p> Signup and view all the answers

    In the caffeine intake experiment, what is the role of noise?

    <p>It is an extraneous variable that does not confound the experiment.</p> Signup and view all the answers

    What is the primary purpose of random assignment in experiments?

    <p>To distribute extraneous variables across conditions</p> Signup and view all the answers

    What does random assignment NOT guarantee?

    <p>Control over all extraneous variables</p> Signup and view all the answers

    Which of the following methods can be used for random assignment?

    <p>Drawing names from a hat</p> Signup and view all the answers

    What is a manipulation check?

    <p>A measure to confirm that the manipulation had the intended effect</p> Signup and view all the answers

    Why is it important to include an exit questionnaire in an experiment?

    <p>To determine if participants could identify the manipulation</p> Signup and view all the answers

    When is it particularly important to perform manipulation checks?

    <p>When participant manipulations are involved</p> Signup and view all the answers

    Which of the following statements about random assignment and sample size is true?

    <p>Larger sample sizes reduce the likelihood of biased outcomes</p> Signup and view all the answers

    What is a potential confound when participants are assigned to different conditions?

    <p>Participants share similar personal experiences</p> Signup and view all the answers

    What is one consequence of using measurement instruments that are not tested for reliability and validity in experimental research?

    <p>Results may be incomparable across studies.</p> Signup and view all the answers

    Which of the following practices can help mitigate threats to external validity in experimental research?

    <p>Conduct treatment manipulation checks.</p> Signup and view all the answers

    What is a potential issue when using inappropriate research designs in experimental research?

    <p>Lack of internal validity.</p> Signup and view all the answers

    Why is it important to ensure tasks used in studies are simple and familiar to participants?

    <p>To avoid unnecessary complexity that may alter responses.</p> Signup and view all the answers

    What does conducting pilot tests with a small sample help researchers achieve?

    <p>It ensures clarity in the roles of the independent and dependent variables.</p> Signup and view all the answers

    What is referred to as systematic variance in a between-subjects design?

    <p>Variability between the means of different treatment groups</p> Signup and view all the answers

    How does systematic variance impact the analysis in experiments?

    <p>It allows for comparison between treatment groups</p> Signup and view all the answers

    What is non-systematic variance primarily attributed to?

    <p>Random chance and individual differences</p> Signup and view all the answers

    In which scenario is between-subjects design considered advantageous?

    <p>When the sample size is limited</p> Signup and view all the answers

    What must be minimized to ensure accurate results in a between-subjects design?

    <p>Non-systematic variance</p> Signup and view all the answers

    When might researchers expect to see the same scores on aggression across groups?

    <p>When experimental conditions are controlled</p> Signup and view all the answers

    What is the primary focus when calculating the F-ratio in an experiment?

    <p>The ratio of systematic variance to non-systematic variance</p> Signup and view all the answers

    What factors can contribute to systematic variance in experimental results?

    <p>Differences caused by exposure to treatment effects</p> Signup and view all the answers

    What is the purpose of matching subjects in pairs during an experiment?

    <p>To control for confounding variables</p> Signup and view all the answers

    What is one key aspect of differential attrition in an experimental study?

    <p>It may lead to groups being non-equivalent.</p> Signup and view all the answers

    In the context of matching across blocks, what is one characteristic on which individuals are matched?

    <p>Age</p> Signup and view all the answers

    How can matched pairs help in controlling individual differences in an experiment?

    <p>By ensuring that pairs have equivalent individual characteristics.</p> Signup and view all the answers

    In an experimental design, what is a common consequence of attrition?

    <p>Loss of equivalence among groups.</p> Signup and view all the answers

    What could be a potential confounding variable in a study examining the effects of a treatment on pain relief?

    <p>Type of pain medication used</p> Signup and view all the answers

    What is one primary advantage of matching individuals in blocks during an experiment?

    <p>It can lead to a balanced distribution of characteristics.</p> Signup and view all the answers

    Which stage in the matching process requires participants to be segregated into pairs based on specific characteristics?

    <p>Measurement and ranking</p> Signup and view all the answers

    What is a key implication of increasing the number of conditions in a study in terms of carryover effects?

    <p>Carryover effects create more bias as the number of conditions increases.</p> Signup and view all the answers

    What is one of the primary disadvantages of using between-subjects designs?

    <p>It necessitates a larger number of participants for valid comparisons.</p> Signup and view all the answers

    Which of the following biases can impact the validity of between-subjects designs?

    <p>Environmental differences</p> Signup and view all the answers

    What is a recommended solution to address assignment bias in experimental research?

    <p>Ensure participants are unaware of their assigned condition.</p> Signup and view all the answers

    In what circumstance is a between-subjects design particularly beneficial?

    <p>When examining faked self-reports of health behavior.</p> Signup and view all the answers

    What is the primary purpose of randomization in experimental designs?

    <p>To ensure that individual differences are equally distributed across treatment conditions</p> Signup and view all the answers

    What distinguishes randomization from random sampling?

    <p>Randomization assigns participants to groups, while random sampling selects them from a larger population.</p> Signup and view all the answers

    Why is it improbable that groups will be perfectly matched through randomization?

    <p>Because there's a possibility of random differences occurring despite equal assignment.</p> Signup and view all the answers

    Which method ensures that participants share critical characteristics prior to assignment?

    <p>Matching participants on pre-existing differences</p> Signup and view all the answers

    What is a limitation of using small sample sizes in experiments?

    <p>It leads to a higher likelihood of randomization errors.</p> Signup and view all the answers

    Which of the following describes how matching can enhance the validity of an experiment?

    <p>It guarantees that groups are equivalent on important predefined variables.</p> Signup and view all the answers

    What is one of the main reasons why random assignment may not guarantee equal groups?

    <p>The inherent variability in small sample sizes can lead to unequal groups.</p> Signup and view all the answers

    What does 'free random assignment' ensure in experimental design?

    <p>Each participant has an equal chance of being assigned to any treatment condition.</p> Signup and view all the answers

    Which statement reflects a common misconception about random sampling?

    <p>It provides equal chances for all participants to be allocated in a study.</p> Signup and view all the answers

    What might be an undesirable outcome if extraneous variables are not controlled in an experiment?

    <p>Confounding factors that obscure the results of the treatment.</p> Signup and view all the answers

    What does a large between-group variance indicate in an experimental design?

    <p>It suggests treatment effects are likely present.</p> Signup and view all the answers

    What is a potential outcome of having large within-group variance?

    <p>Difficulty in identifying treatment effects.</p> Signup and view all the answers

    In the context of the treatment index, what does the F-ratio compare?

    <p>Between-group variance to within-group variance.</p> Signup and view all the answers

    When analyzing group differences, which factor should researchers aim to minimize?

    <p>Within-group differences.</p> Signup and view all the answers

    What is meant by assignment bias in experimental research?

    <p>Differences in participant characteristics due to group allocation.</p> Signup and view all the answers

    Which scenario demonstrates a single-factor multiple-group design?

    <p>Testing driving performance under different phone usage conditions.</p> Signup and view all the answers

    What is the goal of using a large sample size in an experimental study?

    <p>To reduce the stakes of assignment bias.</p> Signup and view all the answers

    Which of the following describes a disadvantage of large within-group variance?

    <p>It can lead to inaccurate conclusions about treatment effects.</p> Signup and view all the answers

    Which factor represents an environmental variable that may impact an experimental study?

    <p>The time of day the experiment is conducted.</p> Signup and view all the answers

    What is a primary disadvantage of using a between-subjects design?

    <p>Variability in participant responses due to differing conditions</p> Signup and view all the answers

    What effect can a within-subjects design have on participants' perception?

    <p>It raises participants' awareness of comparison across conditions</p> Signup and view all the answers

    What is a key characteristic of a strong experimental design?

    <p>Clearly distinct treatment groups.</p> Signup and view all the answers

    Why is standardization of experimental procedures important?

    <p>It ensures all participants experience the same conditions.</p> Signup and view all the answers

    When should a between-subjects design be avoided?

    <p>When similar anchoring is desired across conditions</p> Signup and view all the answers

    What is an implication of the findings from the study comparing between-subjects and within-subjects designs?

    <p>Within-subjects designs yield larger differences between conditions</p> Signup and view all the answers

    What does minimizing individual differences aim to achieve in an experimental study?

    <p>To ensure groups are as similar as possible except for the IV.</p> Signup and view all the answers

    What type of effects do between-subjects designs help avoid?

    <p>Carry-over effects from previous conditions</p> Signup and view all the answers

    In a between-subjects design, what does random assignment aim to achieve?

    <p>Elimination of systematic bias in group assignments.</p> Signup and view all the answers

    What rating scale example illustrates a challenge associated with a between-subjects design?

    <p>Judgments based on different anchors by separate groups</p> Signup and view all the answers

    Which factor is the least likely to affect the internal validity of an experiment?

    <p>Measurement reliability.</p> Signup and view all the answers

    Which of the following is a potential threat to validity associated with within-subjects designs?

    <p>Carry-over effects from previous conditions</p> Signup and view all the answers

    What is a benefit of utilizing a between-subjects design?

    <p>Reduction in participant bias and awareness</p> Signup and view all the answers

    What are the two components of between-subjects (systematic) variance?

    <p>Treatment effects and experimental error</p> Signup and view all the answers

    In non-systematic (within-group) variance, what mainly causes any variability among participants treated alike?

    <p>Chance factors and experimental error</p> Signup and view all the answers

    To evaluate if differences between group means are due to experimental error alone or treatment effects plus experimental error, one must analyze which of the following?

    <p>The variance components in the data</p> Signup and view all the answers

    What is the significance of experimental error in the context of systematic variance?

    <p>It contributes to the total variance interpretation.</p> Signup and view all the answers

    When assessing a study's variance, which type is purely attributed to chance factors?

    <p>Non-systematic variance</p> Signup and view all the answers

    What would be an indication that the differences in aggressive acts across groups are not solely due to experimental error?

    <p>Significant differences in group means</p> Signup and view all the answers

    What type of variance would result from differences between subjects treated identically?

    <p>Non-systematic variance</p> Signup and view all the answers

    Which of the following best describes experimental error in an experiment?

    <p>It encompasses all unaccounted chance variations.</p> Signup and view all the answers

    Which of the following best differentiates random sampling from randomization?

    <p>Random sampling selects participants from a population, while randomization assigns them to groups</p> Signup and view all the answers

    What is a limitation of using randomization in studies with small sample sizes?

    <p>It may not evenly distribute individual differences</p> Signup and view all the answers

    Which of the following steps is NOT part of the process of matching participants in experimental designs?

    <p>Randomly assigning participants to treatment conditions</p> Signup and view all the answers

    Which of the following statements about free random assignment is true?

    <p>Participants have an equal chance of being assigned to any condition</p> Signup and view all the answers

    What is the primary goal of matching subjects on critical variables?

    <p>To control for confounding variables related to the dependent variable</p> Signup and view all the answers

    What does random assignment NOT guarantee in an experimental study?

    <p>Complete elimination of confounding variables</p> Signup and view all the answers

    Which of the following describes the outcome if groups are not created or treated equally?

    <p>The validity of causal conclusions may be compromised</p> Signup and view all the answers

    What is a significant challenge when using between-subjects designs?

    <p>Requires a larger number of participants.</p> Signup and view all the answers

    How can modifiable randomization improve control over study outcomes?

    <p>By enabling researchers to fine-tune group composition as needed</p> Signup and view all the answers

    Which of the following biases can occur in between-subjects designs?

    <p>Subject-expectancy bias.</p> Signup and view all the answers

    What is the primary goal of ensuring equivalent individuals in between-groups design?

    <p>To accurately compare the effects of the independent variable</p> Signup and view all the answers

    What is crucial for ensuring groups are equivalent before manipulation in a between-subjects design?

    <p>Random assignment of participants.</p> Signup and view all the answers

    Which method can help mitigate biases in experiments involving multiple conditions?

    <p>Double-blind design.</p> Signup and view all the answers

    What is a limitation related to generalization in between-subjects designs?

    <p>It reduces external validity due to lack of random sampling.</p> Signup and view all the answers

    What term is used to describe individual differences in scores occurring by chance within groups?

    <p>Non-systematic variance</p> Signup and view all the answers

    What does systematic variance in a between-subjects design reflect?

    <p>Differences among means of treatment groups</p> Signup and view all the answers

    How can researchers minimize non-systematic variance in an experimental study?

    <p>Use a larger sample size</p> Signup and view all the answers

    What potential issue arises from communication between groups during an experiment?

    <p>True effects of treatment may be overshadowed by shared information.</p> Signup and view all the answers

    What is resentful demoralization in the context of experimental design?

    <p>Group members feeling frustrated due to perceived inequities.</p> Signup and view all the answers

    What outcome is commonly associated with a between-subjects design when assessing treatment effects?

    <p>Comparison of mean scores between groups</p> Signup and view all the answers

    What is a potential source of error that researchers must be cautious of in experiments measuring aggression related to cartoon violence?

    <p>Chance factors affecting scores</p> Signup and view all the answers

    Which of the following is an advantage of using a between-subjects design?

    <p>It minimizes the impact of carryover effects.</p> Signup and view all the answers

    In a study comparing aggression scores among three different levels of cartoon violence, what might differences in scores indicate?

    <p>Both treatment and chance factors</p> Signup and view all the answers

    Why are carryover effects a concern in experimentation?

    <p>They can introduce bias that complicates the interpretation of results.</p> Signup and view all the answers

    What minimizes the influence of extraneous variables in a between-subjects design?

    <p>Using random assignment for condition selection.</p> Signup and view all the answers

    Which statistical metric is used to assess the variance between groups in a between-subjects design?

    <p>F-ratio</p> Signup and view all the answers

    In a between-subjects experiment, which factor should researchers aim to control to ensure valid results?

    <p>Extraneous variables</p> Signup and view all the answers

    What is a primary reason that between-subjects designs are popular in psychological research?

    <p>They provide clear comparisons between different treatment conditions.</p> Signup and view all the answers

    What is an observable outcome of carryover effects during an experiment?

    <p>Potential bias in interpreting treatment effects.</p> Signup and view all the answers

    Which statement correctly describes how between-subjects designs handle extraneous variables?

    <p>They aim to minimize the effect of extraneous variables.</p> Signup and view all the answers

    What is a defining feature of a between-subjects design?

    <p>Different groups are assigned to different conditions.</p> Signup and view all the answers

    Which independent variables can ONLY be measured in a between-subjects design?

    <p>Age</p> Signup and view all the answers

    What is one disadvantage of using a between-subjects design?

    <p>Individual differences can introduce variability.</p> Signup and view all the answers

    What are the groups in a between-subjects design compared based on?

    <p>The same dependent variable from different conditions.</p> Signup and view all the answers

    How does randomization contribute to the integrity of a between-subjects design?

    <p>It helps control for confounding variables and individual differences.</p> Signup and view all the answers

    What is the primary goal when calculating the F-ratio in a between-subjects design?

    <p>To compare the means of different groups in relation to the variance among those groups.</p> Signup and view all the answers

    What is a potential outcome if there is too much individual variability in a between-subjects design?

    <p>It can obscure real differences between groups.</p> Signup and view all the answers

    In a between-subjects design, what is meant by 'control condition'?

    <p>A group that receives a baseline measure for comparison.</p> Signup and view all the answers

    What distinguishes a between-subjects design from other experimental designs?

    <p>Each condition is tested on a different group of participants.</p> Signup and view all the answers

    What is the effect of participants experiencing only one level of the independent variable in a between-subjects design?

    <p>Each participant contributes one score to the dependent variable.</p> Signup and view all the answers

    Which of the following independent variables can only be measured using a between-subjects design?

    <p>Gender</p> Signup and view all the answers

    What is a potential advantage of using a between-subjects design?

    <p>It reduces the likelihood of demand characteristics affecting results.</p> Signup and view all the answers

    What role does randomization play in a between-subjects design?

    <p>It helps in equalizing groups on extraneous variables.</p> Signup and view all the answers

    What is one significant challenge associated with a between-subjects design?

    <p>Dealing with variation in individual differences among participants.</p> Signup and view all the answers

    In the context of a between-subjects design, what does the F-ratio primarily assess?

    <p>The ratio of systematic variance to error variance.</p> Signup and view all the answers

    Which of the following describes a characteristic of individual differences in a between-subjects design?

    <p>They often confound the results of the experiment.</p> Signup and view all the answers

    What is one major disadvantage of between-subjects designs in experimental research?

    <p>Requires many participants</p> Signup and view all the answers

    Which bias may arise when both the participants and experimenters are aware of the condition they are in?

    <p>Experimenter-expectancy bias</p> Signup and view all the answers

    Which of the following is a solution to minimize assignment bias in an experimental study?

    <p>Conduct a double-blind experiment</p> Signup and view all the answers

    What is a potential issue when holding subjects constant on extraneous variables in a between-subjects design?

    <p>Reduced external validity</p> Signup and view all the answers

    Why can carryover effects in an experiment create more bias with an increased number of conditions?

    <p>They accumulate across the conditions</p> Signup and view all the answers

    What is the purpose of segregating subjects into matched pairs in an experiment?

    <p>To control for individual differences on the variable of interest</p> Signup and view all the answers

    In a study matching subjects based on IQ, which of the following groups is correctly defined?

    <p>High group: IQ &gt; 110</p> Signup and view all the answers

    What is a potential consequence of differential attrition in an experimental study?

    <p>Differences in outcomes may be attributed to group composition changes</p> Signup and view all the answers

    Which step follows the measurement and ranking of subjects on the desired variable?

    <p>Segregate subjects into matched pairs based on the ranked variable</p> Signup and view all the answers

    In matching across blocks, which of the following is a valid block category related to age?

    <p>Late adolescent: Ages 17-19</p> Signup and view all the answers

    What defines the matching procedure when testing the effects of marijuana on pain relief in cancer patients?

    <p>Patients are matched according to their stage of cancer</p> Signup and view all the answers

    Which of the following statements regarding attrition is correct?

    <p>It only becomes problematic if it affects one group more than another</p> Signup and view all the answers

    Why is measuring and ranking subjects necessary before matching them?

    <p>To control for the variable that influences the effects being studied</p> Signup and view all the answers

    What is a potential impact of diffusion in experimental groups?

    <p>It may mask the true effects of a treatment.</p> Signup and view all the answers

    How can resentful demoralization affect an experimental study?

    <p>It may lead to observed differences having alternate explanations.</p> Signup and view all the answers

    What is an advantage of using a between-subjects design in experiments?

    <p>There is a reduction of carryover effects.</p> Signup and view all the answers

    Why are carryover effects a concern in experimental designs?

    <p>They can introduce bias that is hard to measure.</p> Signup and view all the answers

    What characteristic of scores is maintained in a between-subjects design?

    <p>Each score is independent from other scores.</p> Signup and view all the answers

    In experimental design, what can indirect communication between groups lead to?

    <p>Spreading treatment effects across groups.</p> Signup and view all the answers

    What does the popularity of between-subjects designs primarily stem from?

    <p>Their potential to recognize bias from carryover effects.</p> Signup and view all the answers

    What is one outcome of communication leading to treatment overlap?

    <p>A potential masking of true treatment effects.</p> Signup and view all the answers

    What is the primary purpose of randomization in an experimental study?

    <p>To equalize pre-existing differences among participants</p> Signup and view all the answers

    What is a key distinction between random sampling and randomization?

    <p>Random sampling selects participants while randomization assigns them to groups</p> Signup and view all the answers

    What is the primary goal of matching participants in an experiment?

    <p>To adjust for extraneous variables across groups</p> Signup and view all the answers

    Which method can be employed to achieve free random assignment in an experimental study?

    <p>Conducting a coin toss for group assignment</p> Signup and view all the answers

    In an experiment with small sample sizes, what limitation can affect the effectiveness of randomization?

    <p>Pre-existing differences may not distribute evenly</p> Signup and view all the answers

    What is a potential outcome of not controlling environmental variables in a study?

    <p>Treatment effects may become negligible and undetectable</p> Signup and view all the answers

    How does randomization contribute to internal validity in experimental research?

    <p>It helps ensure that differences in outcomes are due solely to the treatment</p> Signup and view all the answers

    What does a large between-group variance indicate in an experimental study?

    <p>Significant treatment effects</p> Signup and view all the answers

    What is the effect of having large within-group variance on the F-ratio?

    <p>It lowers the F-ratio, making treatment effects harder to observe</p> Signup and view all the answers

    What can be a consequence of matching on critical variables in an experiment?

    <p>Enhanced equality among groups on those variables</p> Signup and view all the answers

    What is a limitation of achieving perfect matching among participants in an experiment?

    <p>It can lead to a reduction in the sample size available for testing</p> Signup and view all the answers

    Which of the following best describes assignment bias?

    <p>Non-random differences in group characteristics at baseline</p> Signup and view all the answers

    What aspect of random assignment theoretically leads to equality in groups?

    <p>It allows every participant an equal chance of being placed in any group</p> Signup and view all the answers

    What is a key goal when using a single-factor analysis of variance (ANOVA)?

    <p>To determine the mean effects of one independent variable on a dependent variable</p> Signup and view all the answers

    Why is it important to minimize within-group differences in a study?

    <p>To enhance the reliability of treatment effects observed</p> Signup and view all the answers

    What does a positive and large F-ratio signify in an experimental study?

    <p>Significant effect of the independent variable</p> Signup and view all the answers

    What do environmental variables refer to in the context of an experiment?

    <p>Characteristics of the experimental setting that may influence results</p> Signup and view all the answers

    Which of the following would be considered a within-group variance?

    <p>Variability caused by measurement errors within a group</p> Signup and view all the answers

    How can researchers reduce individual differences in their study?

    <p>By standardizing treatment procedures and using random assignment</p> Signup and view all the answers

    In the context of experimental research, what does systematic variance refer to?

    <p>Consistent differences attributable to the independent variable</p> Signup and view all the answers

    What does the F-ratio compare in an experimental analysis?

    <p>Between-group variance to within-group variance</p> Signup and view all the answers

    What is a potential threat to internal validity in a study?

    <p>Non-random assignment resulting in unequal groups</p> Signup and view all the answers

    What is the main purpose of using a large sample size in experimental research?

    <p>To reduce the impact of individual variability and confounding factors</p> Signup and view all the answers

    Study Notes

    Experimental Research Strategy

    • This research method aims for a causal explanation
    • It uses high constraints on variables, making it a powerful approach
    • Manipulation of one variable (independent variable) to observe its impact on another (dependent variable)
    • This effect is examined while maintaining consistency in other influencing factors

    Midterm Grades

    • Grades for midterm 1 (multiple choice and short answers) will be posted online by October 27th
    • Final grade is out of 32 points
    • Summary statistics: average multiple choice grade is 24/28 (range: 16-32) and short answer grade is 3/4 (range: 0-4)
    • The overall average was 27/32
    • Exams not returned; students with a score of 22/28 or lower on multiple choice and 2/4 or lower on short answers can view their exam at office hours by October 31
    • Specific office hours for letter ranges are available on page 4.

    Sampling Techniques

    • A researcher wants to equally represent four different religious groups within a sample of 40 people
    • Stratified random sampling or proportionate stratified random sampling would be suitable for that goal

    Validity and Reliability

    • A new anxiety test scores highly similar to a standardized anxiety assessment
    • This indicates high concurrent validity

    Grading Information

    • Multiple Choice: Students who scored 22/28 or lower can attend office hours until October 31
    • Short Answer: Students who scored 2/4 or lower can attend office hours until October 31
    • Students with 23/28 multiple choice or 3/4 short answer can visit office hours the week of November 4-7

    Scoring Short Answers

    • Scores of 0, 1 and 2 are used for short answer questions, and indicate varying levels of completeness.
    • The possible short answer questions include naming and describing, 2 important historical events that shaped psychological ethical guidelines. Examples provided include the Tuskegee syphilis study, Nazi atrocities of scientists, Milgram's experiment, and the Nootka (BC) study.

    Sampling Bias

    • A study using Montreal residents' transportation methods may encounter issues including:
      • Limited sampling locations, potentially omitting other transportation methods (cars, metro, bikes, etc.)
      • Sampling one season, potentially biasing towards only popular outdoor options, and excluding others (like commuting).

    Confounding Variables

    • Caffeine, coffee, or alcohol intake is a confounding variable related to smoking and decreased sleep quality since it positively correlates with both smoking and sleep disruption
      • Stress and anxiety can impact smoking and sleep quality similarly, creating a confounding effect

    Experimental Design Outline

    • Introduction includes elements like problems with understanding causality, experimental control, and experimental groups
    • Unique Attributes of Experimental Design involves Manipulation and Control
    • External validity considers simulations and field studies

    Experimental Strategy

    • Experimental designs are considered the most powerful method
    • They employ high constraints on subject variables.
    • The primary objective of an experiment is to establish cause-and-effect relationships
    • Manipulation of an independent variable determines its impact on a dependent variable while consistently managing other possible influencing factors.

    Establishing Causality

    • Establishing causality requires four fundamental elements:
    • Time order (cause must occur before effect)
    • Co-variation (statistical association)
    • Rationale/explanation (logical explanation for the link)
    • Non-spuriousness (establishing the IV as the sole cause)

    Experimental Conditions

    • Does exposure to music lessons improve IQ Scores ? (Experimental and Control groups and relevant variables)

    Possible Control Groups

    • Placebo control group: participants receive a fake/placebo treatment
    • Waitlisted group: participants who sign up to receive the actual treatment later

    The Experimental Research Strategy

    • The four core elements are manipulation, measurement, comparison, and control.

    Independent/Dependent Variables

    • Independent variable: the variable manipulated, considered the cause
    • Dependent variable: the measured variable, considered the effect

    Between-Group Designs

    • Experimental group: exposed to the treatment
    • Control group: not exposed to the treatment; used for comparison

    Experimental Conditions – Example

    • Examining the impact of Prozac (IV) as an antidepressant treatment on depressive symptoms (DV) using a treatment and placebo control setup.

    Important Considerations: Ebola Example

    • Two main treatments were given during an Ebola outbreak, and how their effectiveness (or not) was observed

    The Experimental Research Strategy (Four Basic Elements)

    • Manipulation: Researcher changes the value of one variable to create different situations
    • Measurement: A second variable is measured to gather data for each condition
    • Comparison: The scores for each condition is compared (scores in each treatment condition)
    • Control: Other variables are held constant to ensure their effects do not interfere with the research

    Four Basic Elements (Diagram)

    • A graphical representation of the steps involved in the manipulation of one variable, measurement of a second, comparison of the results, and control of other variables, in an experimental research strategy.

    Unique Elements of Experimental Research

    • Manipulation & Control are key elements of experimental research.
    • These elements are needed to determine a cause-and-effect relationship, which is the goal of experimental research.

    Manipulation & Directionality

    • The manipulation's goal is to understand causality in the effect between IV and DV
    • One variable (IV) is manipulated (increased/decreased) to see if it impacts the other variable (DV)

    Manipulation & Third Variable Problem

    • Researchers can use manipulations to control the influence of other variables.

    Control - Confounding Variables

    • A special type of extraneous variable that changes with the independent variable. It can mask the true effect of the independent variable.

    Control- Eliminating the Confound

    • Methods to control confounds. - Removing the confound - Holding the variable constant - Matching participants to control the effect of the confound. - Randomizing participants to conditions to minimize the effect of the confound.

    Control - Extraneous vs. Confounding Variables

    • Extraneous variables: any other variables in the experiment impacting results, regardless of the effect on the outcomes.
    • Confounding Variables: Extraneous variables that change systematically with the independent variable. This confounds the result, because it overlaps with the effect of the independent variable.

    Control - Confounding Variables Examples

    • An example of a study to investigate if exposure to music lessons impacts IQ. Possible confounds: the teacher presence and the different teaching styles of the teachers/ instructors.

    Control - Possible Reasons for Experiment Failure

    • Provides example scenarios for why an experiment may not yield the desired result(s). Includes suggestions for improving the study design, such as including more conditions or expanding the number of participants.

    Control - Threats of Internal Validity

    • Explains eight threats to internal validity, including:
    • History
    • Maturation
    • Statistical Regression
    • Selection
    • Experimental Attrition
    • Testing
    • Instrumentation
    • Design contamination

    Control - Threats of External Validity

    • Focuses on four threats to external validity, explaining how these threats can limit the generalisability of the conclusion:
      • Unique program features
      • Effects of Selection
      • Effects of Environment / Setting
      • Effects of History

    External Validity & Experimental Strategies

    • Lab simulations aim to make experiments more like real-world conditions.
    • Field studies take place in a real-world setting.
    • Field studies with animals: examining behaviour that's difficult to replicate in a lab setting.

    Perils for Experimental Designs

    • Issues that can challenge the validity or reliability of an experiment, like inadequate sampling, lacking consideration of alternative causes for results and invalid or unstandardised measurements in experimental designs.

    Ways to Avoid the Perils

    • Discusses methods to enhance experimental rigor and credibility.
      • Using pre-validated materials and task
      • Implementing manipulation checks
      • Conducting pilot testing

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    Related Documents

    McGill Research Methods in Psychology Past Paper PDF
    Psychology 306 Chapter 8: Between-Subjects Design PDF

    Description

    Test your understanding of manipulation and key concepts in experimental research with this quiz. Explore questions about independent and dependent variables, ethical guidelines, and sources of bias. Perfect for students looking to deepen their knowledge of experimental design.

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