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Questions and Answers
A researcher aims to measure anxiety using a new questionnaire. To establish construct validity, what should the researcher primarily demonstrate?
A researcher aims to measure anxiety using a new questionnaire. To establish construct validity, what should the researcher primarily demonstrate?
- The questionnaire comprehensively covers all aspects of anxiety as defined by existing theories.
- The questionnaire yields consistent scores over repeated administrations.
- The questionnaire accurately predicts future occurrences of anxiety-related behaviors.
- The questionnaire correlates strongly with other established measures of anxiety. (correct)
A study on a new teaching method shows promising results in a controlled laboratory setting. What must be established to ensure external validity?
A study on a new teaching method shows promising results in a controlled laboratory setting. What must be established to ensure external validity?
- The results can be replicated in diverse classroom environments with different student populations. (correct)
- The teaching method is consistently applied by all researchers involved in the study.
- The teaching method minimizes the influence of confounding variables within the lab.
- The results are statistically significant and not due to chance.
In an experiment examining the effect of a new drug on cognitive performance, participants in the control group unknowingly take a placebo but report improved focus. Which threat to internal validity is most likely affecting the study?
In an experiment examining the effect of a new drug on cognitive performance, participants in the control group unknowingly take a placebo but report improved focus. Which threat to internal validity is most likely affecting the study?
- Reactivity (correct)
- History
- Instrumentation
- Maturation
A researcher studying the impact of exercise on mood assigns participants to either an exercise or a no-exercise group. Participants in the exercise group are generally more health-conscious and have better diets than those in the no-exercise group. What is the most likely confounding variable in this scenario?
A researcher studying the impact of exercise on mood assigns participants to either an exercise or a no-exercise group. Participants in the exercise group are generally more health-conscious and have better diets than those in the no-exercise group. What is the most likely confounding variable in this scenario?
A researcher uses an established IQ test to measure participants' intelligence at the beginning and end of a study. To ensure the reliability of the measurements, which type of reliability is MOST important to assess?
A researcher uses an established IQ test to measure participants' intelligence at the beginning and end of a study. To ensure the reliability of the measurements, which type of reliability is MOST important to assess?
Researchers are studying the effectiveness of two different therapies for anxiety: Therapy A and Therapy B. To minimize confounding variables and make causal claims, which method should they employ when assigning participants to treatment groups?
Researchers are studying the effectiveness of two different therapies for anxiety: Therapy A and Therapy B. To minimize confounding variables and make causal claims, which method should they employ when assigning participants to treatment groups?
A study measures participants' height, classifying them into categories: short, medium, and tall. What type of measurement scale is being used?
A study measures participants' height, classifying them into categories: short, medium, and tall. What type of measurement scale is being used?
A researcher compares the effectiveness of a new drug by giving the drug to one group of participants and a placebo to another group. What type of experimental design is this?
A researcher compares the effectiveness of a new drug by giving the drug to one group of participants and a placebo to another group. What type of experimental design is this?
A researcher aims to equate groups on key characteristics like age and education before randomly assigning them to different treatment conditions. Which method is the researcher employing to control for a priori differences?
A researcher aims to equate groups on key characteristics like age and education before randomly assigning them to different treatment conditions. Which method is the researcher employing to control for a priori differences?
In a study where participants complete multiple tasks, performance on earlier tasks affects performance on later tasks due to fatigue. What is this effect called, and how can it be controlled?
In a study where participants complete multiple tasks, performance on earlier tasks affects performance on later tasks due to fatigue. What is this effect called, and how can it be controlled?
Flashcards
Construct validity
Construct validity
Whether independent and dependent variables truly measure what they are intended to measure.
External validity
External validity
The extent to which results can be generalized across subjects, variables, and settings.
Internal validity
Internal validity
Concerns the validity of causal or explanatory conclusions in an experiment.
Confounding
Confounding
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Reliability
Reliability
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Random assignment
Random assignment
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Random sampling
Random sampling
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Between-subjects design
Between-subjects design
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Within-subjects design
Within-subjects design
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Complete counterbalancing
Complete counterbalancing
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Study Notes
- Study notes on exam review questions are provided below.
Construct Validity
- Determines if variables truly measure their intended targets.
- Subject reactivity, confounding variables, and random errors threaten validity.
- Minimization strategies include deception, blind and double-blind procedures, operational definitions, and standardized protocols.
External Validity
- External validity dictates result generalization across subjects, variables, and settings.
- Establishing external validity ensures representativeness through replication and field studies.
Internal Validity
- Internal validity confirms the validity of causal conclusions in an experiment.
- History: Events outside the study influence results.
- Maturation: Changes in subjects over time.
- Testing: Effects of repeated testing.
- Instrumentation: Changes in measurement tools.
- Attrition: Loss of participants.
- Selection: Differences in groups before the experiment.
Confounding Variables
- Confounding occurs when an uncontrolled variable systematically changes with the independent variable.
- Undermines the ability to draw experiments' conclusions.
Reliability
- Reliability means the consistency of measurements.
- Minimizing random error improves reliability.
- Statistical reliability ensures results aren't due to chance (p < .05).
- Experimental reliability replicates results across experiments.
- Test reliability measures using test-retest, split-half methods.
Random Assignment and Random Sampling
- Random assignment allocates subjects randomly, reducing confounding variables.
- Random sampling ensures every population member is equally likely to be selected.
Measurement Scales
- Measurement scales differ by magnitude of attribute, intervals between values, and zero point.
- Nominal scales categorize data, such as gender.
- Ordinal scales rank orders data with unequal intervals, like race placements.
- Interval scales have equal intervals but no true zero, such as temperature in Celsius.
- Ratio scales have equal intervals and a true zero, like weight.
Identifying Measurement Scales
- Ratio scales allow stating one value is a multiple of another.
- Ordinal scales are used for rank-ordering, like ice cream preferences.
- Nominal scales are used for coding emotional responses.
Between- vs. Within-Subjects Designs
- Between-subjects assigns different treatments to different groups.
- Within-subjects exposes all subjects to all treatments.
Controlling for a Priori Differences
- Matching subjects ensures similar characteristics but may mismatch other variables.
- Randomization ensures equal distribution of confounding variables.
Carry-Over Effects
- Carry-over effects arise when prior conditions affect subsequent performance.
- Randomization controls these effects.
- Counterbalancing manages carry-over effects.
Complete Counterbalancing
- Complete counterbalancing tests all possible orders of conditions.
- Becomes impractical with conditions requiring n! or orderings.
Incomplete Counterbalancing
- Incomplete counterbalancing ensures each condition equally appears in experiment phases.
Balanced Latin Square
- A Balanced Latin Square is a formula-based arrangement: each condition appears in every order position.
Mixed Design
- A mixed design contains both between-subjects and within-subjects variables.
Factorial Design
- A 2×4×3 factorial design has three independent variables.
- Levels of each: 2, 4, and 3
- Groups needed: 2 × 4 × 3 = 24
Main Effect and Interaction
- A main effect is one independent variable's impact, ignoring others.
- Interaction arises when one independent variable's impact depends on another.
Within-Groups Design
- A 2×4 within-groups design has two independent variables.
- Levels: 2 and 4
- Groups needed: 1 (all subjects experience all conditions).
Randomization
- Complete randomization randomly orders conditions.
- Block randomization ensures each condition appears once before repetition.
Balanced Latin Square Advantage
- A balanced Latin Square ensures each treatment occurs in all positions equally to avoid order effects.
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