Podcast
Questions and Answers
The sample is the group of participants, treatments, and situations on which the study is conducted and a key issue is how these samples are ______.
The sample is the group of participants, treatments, and situations on which the study is conducted and a key issue is how these samples are ______.
selected
The ideal ways to select a sample are through random sampling and ______ random sampling.
The ideal ways to select a sample are through random sampling and ______ random sampling.
stratified
The purpose of random sampling is to select a sample so that it represents the larger ______.
The purpose of random sampling is to select a sample so that it represents the larger ______.
population
Stratified random sampling involves stratifying a population on some ______ before random selection.
Stratified random sampling involves stratifying a population on some ______ before random selection.
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Researchers often rely on ______ to participate in their studies.
Researchers often rely on ______ to participate in their studies.
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The use of random sampling helps to ensure that the sample is ______ of the population.
The use of random sampling helps to ensure that the sample is ______ of the population.
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Challenges in getting contact information can make ______ sampling difficult or impossible.
Challenges in getting contact information can make ______ sampling difficult or impossible.
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Before randomly selecting a sample for normative data, the population should be stratified by ______.
Before randomly selecting a sample for normative data, the population should be stratified by ______.
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Random assignment helps to ensure that the groups are equivalent at the beginning of the _____
Random assignment helps to ensure that the groups are equivalent at the beginning of the _____
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Random matched assignment requires matching participants for a characteristic to ensure representation across _____
Random matched assignment requires matching participants for a characteristic to ensure representation across _____
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Intact groups refer to preexisting _____ used for assigning participants in research.
Intact groups refer to preexisting _____ used for assigning participants in research.
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Post hoc justification provides an explanation after the event and aims to show that the sample is representative of the _____
Post hoc justification provides an explanation after the event and aims to show that the sample is representative of the _____
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One challenge of recruiting is that volunteers are likely to be more interested in the study than people from a random ______.
One challenge of recruiting is that volunteers are likely to be more interested in the study than people from a random ______.
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Internal validity assesses whether the experimental _____ made a difference in the experiment.
Internal validity assesses whether the experimental _____ made a difference in the experiment.
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External validity questions the _____ of the findings across different populations and settings.
External validity questions the _____ of the findings across different populations and settings.
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Convenience sampling involves researchers being interested in specific types of people who would not be present in large ______ if recruited from the general population.
Convenience sampling involves researchers being interested in specific types of people who would not be present in large ______ if recruited from the general population.
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Controlling independent variables is critical for increasing _____ validity in research.
Controlling independent variables is critical for increasing _____ validity in research.
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Snowball sampling is when researchers are recruiting from even more ______ groups, for example, specific chronic diseases.
Snowball sampling is when researchers are recruiting from even more ______ groups, for example, specific chronic diseases.
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Researchers must often forgo random assignment when studying conditions like _____ disease.
Researchers must often forgo random assignment when studying conditions like _____ disease.
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All true experimental designs REQUIRE that the groups within the sample be randomly ______.
All true experimental designs REQUIRE that the groups within the sample be randomly ______.
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The procedures used for random assignment are the ______ regardless of how the sample was selected.
The procedures used for random assignment are the ______ regardless of how the sample was selected.
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Researchers examining the effects of chemotherapy on cardiovascular function in breast cancer patients often start with ______ sampling.
Researchers examining the effects of chemotherapy on cardiovascular function in breast cancer patients often start with ______ sampling.
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Mailed invitations, local media, and social media advertisements are methods used for ______ recruitment.
Mailed invitations, local media, and social media advertisements are methods used for ______ recruitment.
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In the case of convenience sampling, Canadian national team sport programs typically carry ______ athletes.
In the case of convenience sampling, Canadian national team sport programs typically carry ______ athletes.
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The results are not applicable to ______ at large!
The results are not applicable to ______ at large!
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Untended events that occur during the treatment are part of the threat known as ______.
Untended events that occur during the treatment are part of the threat known as ______.
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The process of participants maturing during repeated testing is known as ______.
The process of participants maturing during repeated testing is known as ______.
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The learning effect of one test on subsequent administrations is called ______.
The learning effect of one test on subsequent administrations is called ______.
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Changes in instrument calibration during the experiment lead to different results due to ______.
Changes in instrument calibration during the experiment lead to different results due to ______.
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Factors like aging and fatigue are examples of ______ that can affect experiment outcomes.
Factors like aging and fatigue are examples of ______ that can affect experiment outcomes.
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Improvement in fitness unrelated to the treatment could be classified under ______ threats.
Improvement in fitness unrelated to the treatment could be classified under ______ threats.
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The learning effect from repeated ______ can impact the reliability of test results.
The learning effect from repeated ______ can impact the reliability of test results.
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Treatments that are effective in constrained situations may not be effective in less constrained ______.
Treatments that are effective in constrained situations may not be effective in less constrained ______.
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The ______ effect occurs when participants' performances change due to attention from researchers.
The ______ effect occurs when participants' performances change due to attention from researchers.
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Multiple-treatment ______ occurs when previous treatments influence subsequent ones.
Multiple-treatment ______ occurs when previous treatments influence subsequent ones.
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Randomization controls for history and ______ in experimental groups.
Randomization controls for history and ______ in experimental groups.
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A control group receives a false treatment known as a ______.
A control group receives a false treatment known as a ______.
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In a blind setup, participants do not know if they are receiving the experimental or ______ treatment.
In a blind setup, participants do not know if they are receiving the experimental or ______ treatment.
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Controlling threats to internal validity includes strategies like randomization, placebo, and ______ setup.
Controlling threats to internal validity includes strategies like randomization, placebo, and ______ setup.
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Statistical ______ and selection biases are controlled through random group formation.
Statistical ______ and selection biases are controlled through random group formation.
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Statistical regression occurs when groups are selected based on ______ scores and are not random.
Statistical regression occurs when groups are selected based on ______ scores and are not random.
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Selection bias occurs when groups are formed on some basis other than ______.
Selection bias occurs when groups are formed on some basis other than ______.
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Experimental mortality refers to the loss of participants from comparison groups for ______ reasons.
Experimental mortality refers to the loss of participants from comparison groups for ______ reasons.
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Selection-maturation interaction occurs when one group is selected due to a specific ______, while the other does not have this characteristic.
Selection-maturation interaction occurs when one group is selected due to a specific ______, while the other does not have this characteristic.
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Expectancy is a threat to internal validity in which the researcher anticipates that certain ______ will occur.
Expectancy is a threat to internal validity in which the researcher anticipates that certain ______ will occur.
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Reactive effects of testing occur when the pretest makes the participant more aware of the upcoming ______.
Reactive effects of testing occur when the pretest makes the participant more aware of the upcoming ______.
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When a group is selected based on some characteristic, the treatment may work only on groups possessing that ______.
When a group is selected based on some characteristic, the treatment may work only on groups possessing that ______.
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The loss of participants due to sickness or lack of interest is an example of ______.
The loss of participants due to sickness or lack of interest is an example of ______.
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Study Notes
Experimental & Quasi-Experimental Research
- Chapter 18 covers experimental and quasi-experimental research.
- The presenter is Dr. Andrew S. Perrotta from the University of Windsor.
Learning Objectives
- How to select a sample for research
- Controlling for internal and external validity
Ways to Select a Sample
- A sample is the group of participants, treatments, and situations a study is based upon.
- How these samples are selected is crucial.
- Random sampling and stratified random sampling are ideal methods for selecting a sample representative of the population.
- Finding contact information and accessing the whole population can make random sampling difficult.
Random Sampling
- Random sampling aims to create a sample that reflects the larger population, allowing conclusions from the sample to apply to the broader population.
- Random sampling helps ensure the sample is representative of the population.
- A population is the entire group of interest in the research question.
Example of Random Sampling
- Protein supplementation after competition in female hockey players maintains lean body mass throughout the season, except when resistance exercise is not part of the routine.
- Similar results are most likely in other women's U-Sport programs.
Example of Stratified Random Sampling
- To create norms for a physical fitness test for grades 4 through 8 in a school district, the student population should first be segmented by age, before random sample selection.
Voluntary Sample
- Researchers frequently recruit volunteers.
- Methods of recruitment often include flyers, local media, social media ads, and face-to-face recruitment.
- Volunteers are inclined to be more involved in the study than a randomly selected group, so these methods may result in samples not being reflective of the general population.
Convenience Sampling
- Convenience sampling targets specific types of people (e.g., Canadian national team athletes).
- Such samples don't reflect the general population.
Snowball Sampling
- Snowball sampling recruits more participants based on recommendations from other participants .
- For example, researchers studying the effects of chemotherapy on cardiovascular function in breast cancer patients might ask patients to suggest other interested patients in cancer support groups.
Ways to Assign Participants to Groups
- Researchers use random assignment, assigning participants to groups randomly (control, treatment)
- Random assignment does not affect the process of selecting the sample.
Random Assignment
- All true experimental designs need random assignment of participants to groups in the sample.
- It helps ensure that the groups are similar at the start of the experiment.
Random Matched Assignment
- Random matched assignment aims to balance characteristics (such as age or fitness) amongst groups.
- For instance, to have equal age and VO2 Max among groups in an experiment.
Intact Groups
- These are groups that already exist (e.g., Parkinson's patients vs. non-patients).
- They aren't ideally created by random assignment, but if no other option, researcher can use them.
Post Hoc Justifications
- Post hoc justifications offer explanations for comparisons of intact groups after they have been set.
- This is a method to try and support sample representativeness
Sources of Invalidity Within Research Methods
- Internal validity is important for research experiments; it ensures the treatment actually caused the observed effect without outside factors impacting the results.
- External validity examines whether results can be generalized to other populations, settings, or treatments.
Threats to Internal Validity
- History (events during the study) can affect results.
- Maturation (changes in participants over time e.g., fatigue) can impact results.
- Testing (repetition of tests can bias results).
- Instrumentation (changes in instruments affect results).
- Statistical Regression (extreme scores become less extreme).
- Selection bias (groups are dissimilar before treatment).
- Experimental mortality (loss of participants).
- Selection/maturation interaction (initial group differences interact with maturation).
- Expectancy (researcher's expectations influence results).
Controlling Threats to Internal Validity
- Randomization helps control for historical events and maturation by evenly distributing these across groups.
- Placebo groups provide a control for expectations.
- Blind setups protect against researcher bias.
- Double blind setups protect against both researcher and participant biases.
Threats to External Validity
- Reactive or interactive effects of testing (participants react differently to treatment after being tested).
- Interaction of selection bias and treatment (treatments may work only on specific groups).
- Reactive effects of experimental treatment (results in specific contexts may not apply to real-world settings).
- Hawthorne effect (participants change behaviors when observed).
- Multiple-treatment interference (effects of previous treatments affect later treatments).
Controlling Threats to External Validity
- Ensuring the experimental environment is similar to the conditions faced by the subjects in the real world can help generalize findings more successfully.
- Using appropriate methodologies is key to understanding and mitigating external threats.
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Description
This quiz focuses on Chapter 18, which covers experimental and quasi-experimental research methods. Delve into topics such as selecting samples, ensuring validity, and understanding various sampling techniques like random and stratified random sampling. Gain insights from Dr. Andrew S. Perrotta's presentation to enhance your research skills.
