Research Sampling Techniques Quiz
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Questions and Answers

What is the primary purpose of random sampling in research?

  • To provide biased results
  • To select non-representative samples
  • To ensure the sample is representative of the population (correct)
  • To limit the study to a specific group

    • Stratified random sampling is used only when the population is homogeneous.

    False

    What is a disadvantage of using random sampling?

    It can be difficult to access contact information and reach the entire population.

    In _______ sampling, the population is divided based on a specific characteristic before random selection.

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

    Match the sampling methods with their descriptions:

    <p>Random Sampling = Sample selected to represent the entire population Stratified Random Sampling = Population divided into layers before sampling Voluntary Sample = Participants select themselves to be in the study Convenience Sampling = Sample obtained from easily accessible participants</p> Signup and view all the answers

    Which of the following is a method of recruiting participants for voluntary sampling?

    <p>Flyer postings</p> Signup and view all the answers

    The main goal of controlling for internal and external validity is to increase the confidence in findings.

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

    Define the term 'population' in the context of research.

    <p>The entire group that is of interest relative to the research question.</p> Signup and view all the answers

    What is a major challenge of recruiting volunteers for a study?

    <p>Volunteers might not represent the general population.</p> Signup and view all the answers

    Convenience sampling involves recruiting individuals randomly from the general population.

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

    What sampling method involves participants recruiting others they know?

    <p>Snowball sampling</p> Signup and view all the answers

    A random sampling method requires that the groups within the sample be _______.

    <p>randomly assigned</p> Signup and view all the answers

    Match the recruitment method with its description:

    <p>Local media &amp; social media advertisements = Using platforms to reach a broader audience Mailed invitations = Directly reaching out to potential volunteers Face-to-face recruitment = Personal interaction to engage potential participants Snowball sampling = Participants recruit other eligible individuals</p> Signup and view all the answers

    How many participants are in each group if there are 40 participants and 4 groups?

    <p>10 participants</p> Signup and view all the answers

    Random assignment is concerned with selecting the sample for the study.

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

    What is one characteristic of convenience sampling mentioned?

    <p>Specific types of people</p> Signup and view all the answers

    What is the purpose of using a random assignment generator in experiments?

    <p>To allow equal representation in all groups from the start</p> Signup and view all the answers

    Post hoc justification is provided before the event has occurred.

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

    What is the focus of internal validity in research?

    <p>Controlling independent variables to eliminate rival hypotheses.</p> Signup and view all the answers

    Random matched assignment is used to match participants for a characteristic such as __________.

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

    Which of the following describes intact groups in research?

    <p>Groups based on pre-existing conditions</p> Signup and view all the answers

    Match the terms with their correct definitions:

    <p>Internal Validity = Controlling independent variables in an experiment External Validity = Generalizability of findings to broader populations Random Assignment = Assigning participants to groups using a randomized method Post Hoc Justification = An explanation provided after the event has occurred</p> Signup and view all the answers

    Internal validity is unrelated to the interpretability of experimental results.

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

    What are the two main questions asked by external validity?

    <p>To what populations can the effect be generalized? What settings or treatment variables can this effect apply to?</p> Signup and view all the answers

    What is a primary threat to internal validity that occurs due to unintended events during treatment?

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

    Maturation refers to the effects of aging, fatigue, or hunger during an experiment.

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

    What is the term used for changes in instrument calibration that can lead to different results in research?

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

    The results obtained from highly controlled research settings may lack __________ in application to broader society.

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

    Which of the following can be a result of 'testing' as a threat to internal validity?

    <p>Learning effects from previous tests</p> Signup and view all the answers

    Match the threats to internal validity with their descriptions:

    <p>History = Unintended events during treatment Maturation = Natural participant changes over time Testing = Effects of previous tests on current performance Statistical regression = Selection based on extreme scores</p> Signup and view all the answers

    Statistical regression can occur when groups are randomly selected.

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

    Name one reference that discusses threats to internal validity.

    <p>Campbell and Stanley</p> Signup and view all the answers

    What is the Hawthorne effect?

    <p>Changes in participant performance due to attention from researchers</p> Signup and view all the answers

    Multiple-treatment interference occurs when a participant receives only one type of treatment.

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

    Name one method researchers use to control threats to internal validity.

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

    In a double-blind setup, neither the __________ nor the participant knows which treatment is being received.

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

    What role does a placebo group play in experiments?

    <p>To determine the effectiveness of the real treatment</p> Signup and view all the answers

    Only the participant needs to be blinded in a blind setup.

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

    Randomization helps control for _____ effects that can occur with non-randomly formed groups.

    <p>statistical regression</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>Placebo = A control group that receives no active treatment Randomization = Assignment of participants to groups based on chance Hawthorne effect = Changes in performance due to observation Double-blind = Both participant and experimenter are unaware of treatment assignment</p> Signup and view all the answers

    What is selection bias?

    <p>Groups formed based on non-random criteria.</p> Signup and view all the answers

    Experimental mortality only involves random reasons for participants dropping out.

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

    What are the threats to internal validity mentioned in the content?

    <p>Selection bias, experimental mortality, selection-maturation interaction, expectancy.</p> Signup and view all the answers

    The interaction of _____ bias and experimental treatment indicates that a treatment may only be effective on groups with specific characteristics.

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

    Which of the following is a threat to external validity?

    <p>Reactive or interactive effects of testing</p> Signup and view all the answers

    Treatments that are effective in laboratory settings are usually effective in less constrained settings.

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

    Match the following concepts to their definitions:

    <p>Selection bias = Formation of groups based on non-random criteria Experimental mortality = Loss of participants for nonrandom reasons Expectancy = Researcher anticipating certain outcomes Reactive effects = Increased participant awareness due to pretesting</p> Signup and view all the answers

    Give an example of a situation where reactive effects of experimental treatment might occur.

    <p>A fitness test before a workout program that motivates participants to improve their performance.</p> Signup and view all the answers

    Study Notes

    Experimental & Quasi-Experimental Research

    • This chapter covers experimental and quasi-experimental research methods.
    • It details how to select samples and control for internal and external validity.

    Learning Objectives

    • How to select a sample for research validity.
    • Controlling for internal and external validity.

    Ways to Select a Sample

    • A sample is the group of participants, treatments, and situations researched.
    • Random sampling and stratified random sampling are ideal ways to select a sample that represents the population.
    • Random sampling is often difficult, potentially impossible, due to challenges in contacting the entire population.

    Random Sampling

    • The purpose of random sampling is to ensure the sample represents the wider population, allowing inferences from the sample to be projected to the broader population.
    • Random sampling helps ensures representativeness of the sample.
    • Population is the entire group for research questions.

    Example – Protein Supplementation

    • Protein supplementation after competition maintains fat-free mass in female hockey players throughout the season.
    • This observation can be expected in other women's U-Sport hockey programs.

    Example – Random Sampling

    • Data shows the typical error in DEXA, gym+field hockey (12 months), and field hockey (4 months).

    Stratified Random Sampling

    • Stratified random sampling first stratifies a population before random selection of the sample.
    • Stratifying involves organizing into stable layers based on specific characteristics.
    • Example: Studying physical fitness in grades 4-8 requires stratifying the population by age to create a relevant sample to gather normative data.

    Voluntary Sample

    • Researchers often rely on volunteers (recruited via flyers, media, online ads, or in-person contact).
    • Volunteers are more interested in a study compared to a randomly selected sample.
    • Findings from this method might not generalize to the wider population.

    Convenience Sampling

    • Convenience sampling selects participants readily available.
    • Specific types of people might not be present in large numbers using random methods.
    • Example: Canadian national team sport programs usually have 18-25 athletes, not a complete representation of the general population.

    Snowball Sampling

    • Researchers recruit from extremely specific groups (e.g., specific chronic diseases).
    • The initial sample might be from convenience sampling.
    • Current participants recruit other eligible individuals via word of mouth.
    • Example: Examining effects of chemotherapy on cardiovascular function in breast cancer patients, enlisting patients during cancer survival meetings.

    Ways to Assign Participants to Groups

    • Selecting participants for control and treatment groups is done through random sampling and random assignment.
    • Random assignment does not relate to random sampling. These are independent processes.

    Random Assignment

    • All true experimental designs require random assignment of groups within the sample.
    • Random assignment criteria do not change based on methods used to gather the initial sample.

    Random Assignment Procedures

    • Each participant receives a unique ID (01-40 for 40 participants in the study) to be assigned to groups.
    • Random assignment generators (MS Excel) are used to assign participants to groups.
    • This process creates equivalent groups at the study baseline.

    Random Matched Assignment

    • First, match participants across groups based on a specific characteristic.
    • The aim is to ensure each group has a similar mean age, VO2 Max, etc., to account for a selection bias.

    Intact Groups

    • Researchers sometimes must assign participants to existing groups (based on a condition or pre-existing groups).
    • This method is not considered experimental.

    Post Hoc Justifications

    • Describes why a sample is considered representative of the population.
    • This occurs after the event (experiment) has occurred.

    Sources of Invalidity within Research Methods

    • Internal validity: Determines if the experimental treatments created a difference in the instance.
    • External validity: Assesses generalizability to other populations, settings, or treatments.

    Internal Validity

    • Ensuring internal validity involves controlling all independent variables.
    • Controlling independent variables helps to minimize any rival explanations of the observed result in the dependent variable.
    • However, gaining internal validity can make it more difficult to generalize (external validity) results to a wider population.

    Example – Internal Validity

    • Shows data points for the effects of yoga on plasma volume and cardiovascular performance in elite female hockey players.

    Threats to Internal Validity

    • History: External events unrelated to the treatment affecting the outcome.
    • Maturation: Changes in participants over time (e.g., fatigue).
    • Testing: Effects of repeated testing.
    • Instrumentation: Changes in measure.
    • Statistical regression: Selection based on extreme scores.
    • Selection biases: Groups aren't formed randomly..
    • Experimental mortality: Participants dropping out for reasons unrelated to the treatment.
    • Selection-maturation interaction: Differences in characteristics between groups influencing maturation.
    • Expectancies: Researchers' expectations influencing outcomes.

    Threats to External Validity

    • Reactive or interactive effects of testing: Participants modify their responses to subsequent treatments because the pre-test.
    • Interaction of selection bias and experimental treatment: Treatment effects vary depending on participant characteristics.
    • Reactive effects of experimental treatment: Treatments effective in constrained situations might not be in less constrained ones.
    • Hawthorne effect: Participants' performance changes because of attention.
    • Multiple-treatment interference: Previous treatments influence subsequent ones.

    Controlling Threats to Internal Validity

    • Randomization: Ensuring historical events, maturation, and statistical regression are evenly distributed across the groups.
    • Placebo: Control group receives a false treatment.
    • Blind setup: Participants don't know which treatment they are receiving.
    • Double-blind setup: Neither participants nor researchers know which treatment is given.

    Controlling for Internal Validity– Gold Standard

    • Randomized, double-blind controlled studies are considered the gold standard in intervention-based research.
    • The main advantage of using randomized, double-blind, controlled trials (DBRCT) is the ability to establish cause and effect relationships between variables.

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    Experimental & Quasi-Experimental Research Lecture Notes PDF

    Description

    Test your knowledge on various research sampling techniques through this engaging quiz. Explore concepts such as random sampling, stratified sampling, and convenience sampling, and how they influence research validity. Perfect for students and professionals alike!

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