Research methods part 2 Flashcards
What makes a sample representative?
A representative sample reflects the wider population accurately, allowing generalization of results.
What are the three principles of participant selection?
The principles are suitability, sample size, and accessibility.
Define “suitability” in participant selection.
Suitability ensures participants match characteristics needed for research, defined by inclusion and exclusion criteria, such as demographics, diagnoses, or availability.
How is sample size determined?
Through statistical methods like power analysis to ensure the sample is large enough to detect effects but not unnecessarily large to conserve resources.
What is power in research, and what is a good power value?
Power is the probability of correctly rejecting a false null hypothesis. A power value of 80% or higher is generally considered valid.
What are the two main types of hypotheses in hypothesis testing?
Null Hypothesis (H₀): Assumes no effect or difference between study groups.
Alternative Hypothesis (H₁): Assumes there is an effect or difference between study groups.
What does “accessibility” refer to in participant selection?
Accessibility involves the logistical, ethical, and practical methods of recruiting participants, such as sampling procedures and participant agreements.
What is the difference between probability and non-probability sampling?
Probability Sampling: Every member of the population has a known chance of being selected. Example: Randomly selecting 100 students from a list of all university students using a lottery system.
Non-Probability Sampling: Participants are chosen based on convenience or other non-random criteria. Example: Surveying students in the library at a specific time because they are readily available.
What are common types of probability sampling?
Simple Random Sampling: Equal chance for everyone. Example: Drawing names from a hat.
Systematic Random Sampling: Select every k-th person. Example: Every 10th person on a list.
Cluster Sampling: Randomly select groups, not individuals. Example: Survey all students in 10 randomly chosen schools.
Stratified Sampling: Divide into groups, then randomly sample equal amount. Example: Group students into strata based on their year (freshmen, sophomores, juniors).
Calculate Proportions: If you want to survey 100 students:
Freshmen: 50% → 50 students
Sophomores: 30% → 30 students
Juniors: 20% → 20 students
Random Sampling Within Each Stratum: Randomly select 50 freshmen, 30 sophomores, and 20 juniors.
What is convenience sampling in non-probability sampling?
Selecting participants based on their availability or ease of access.
Example: A researcher surveys students sitting in a campus cafeteria because they are readily available.
What is the difference between cluster and stratified sampling?
Cluster Sampling: Randomly select entire groups (clusters) and survey everyone in them.
Example: Choose 3 cities and survey all residents.
Stratified Sampling: Randomly sample individuals from all subgroups (strata).
Example: Sample 30% men and 70% women to match population ratio.
Describe quota sampling and how it differs from stratified sampling.
Quota Sampling:
You need 50 males and 50 females for a study. You go to a park and ask any male or female you see until you reach 50 of each. (non propperbility)
Stratified Sampling:
You have a list of all males and females in your population. You split them into male and female groups, then randomly select 50 from each group using a lottery or software. (propperbillity)
What is snowball sampling?
A non-probability method where current participants help recruit more participants, often used for hard-to-reach groups.
Example: If you’re studying underground musicians, you start with one musician who introduces you to others in their network, and the process continues.
What are the steps for systematic random sampling?
Create a List: Compile a list of every member in the population.
Example: A list of 1,000 students at a university.
Determine Sampling Interval (k): Divide the population size (N) by the desired sample size (n).
Example: For 1,000 students and a sample of 100,
𝑘
=
10
k=10.
Randomly Select a Starting Point: Pick a random number between 1 and
𝑘
k.
Example: If the starting point is 4, select every 10th person starting from the 4th.
Select Participants: Include individuals at positions 4, 14, 24, 34, and so on.
What are common types of data collection techniques?
Interviews: Asking participants directly.
Example: A psychologist interviews clients about their anxiety symptoms.
Questionnaires: Written surveys to gather responses.
Example: Measuring opinions about remote learning through an online form.
Observation: Watching and recording behaviors.
Example: Observing children’s play behavior in a daycare.
Performance Tests: Assessing participants’ abilities or skills.
Example: IQ tests.
Physiological Measures: Measuring biological responses.
Example: Heart rate monitoring during stress experiments.
What is Cronbach’s Alpha?
Cronbach’s Alpha is a critical tool in research and testing to ensure scales and questionnaires are
reliable.
Cronbach’s Alpha -> It indicates how well the items in a scale measure the same underlying concept
or construct.
What are the advantages of in-person interviews?
High response rates.
Allows close personal interaction with respondents.
What are the four main ways to conduct surveys?
In-person interviews.
By telephone.
Through the mail.
On the internet.
What are the main types of interview structures?
Structured: Fixed questions, no deviation.
Example: Asking every participant the same set of predefined questions.
Semi-structured: Mix of predefined and open-ended questions.
Example: Exploring general work satisfaction with room for deeper responses.
Unstructured: Broad, open-ended, informal discussions.
Example: “Tell me about your childhood” in a clinical setting.
What is a Likert scale in questionnaires?
A psychometric scale used to measure agreement or frequency on a statement.
Example:
Strongly Disagree (1)
Disagree (2)
Neutral (3)
Agree (4)
Strongly Agree (5)
What is social desirability bias in questionnaires?
When participants respond in a way they think is most socially acceptable rather than truthfully.
Example: Underreporting alcohol consumption or overreporting exercise habits.
What are performance tests?
A: Standardized measures assessing psychological variables like intelligence or attention.
Example: Administering the Stroop Test to measure cognitive flexibility.
What is internal consistency in standardized instruments?
A measure of how well test items assess the same construct.
Example: A personality test using Cronbach’s Alpha to ensure reliability.
What are latent traits?
Latent traits are internal characteristics that cannot be directly observed but can be inferred through responses to specific questions or behaviors.
Example: Extroversion is a latent trait measured using questions like, “Do you enjoy being the center of attention?”