M6: Foundations of Quantitative Research - Variables Flashcards
What is a Variable
A property or characteristic that can takeon
different numerical values
None in qualitative research
What are Independent Variables (IV)?
The variable or “part of the experiment” you are manipulating
- The “cause” of the dependent variable (DV) scores
- Levels of the independent variable
determinism - cause and effect
What are Dependent Variables?
(DV; Outcome variable)
– The “effect” of the independent variable (IV)
– Measured by the researcher
determinism - cause and effect
What type of study is this?
Experimental Study
IV: (1) Type of Knee Support (2 levels)
DV: Knee Pain (pain scale)
For Non-Experimental Studies
What is the Predictor Variable?
– The presumed “cause” in a correlational (non-experimental) study
– Measured by the researcher
For Non-Experimental Studies
What is the Criterion Variable?
– The presumed “effect” in a correlational (nonexperimental) study
– Measured by the researcher
Need to measure to 2 things
PV: Time to Rehab (x-axis)
CV: Time to Play (y-axis)
Positive Correlation. Longer it takes to start rehab, longer it takes to return to sport
Unethical study design. cant force someone to wait for surgery
- Correlation
- Predictor - total and specific types of physical activity
- Criterion - risk of age-related cataract in women & men
- Swedish Adults aged 45-83
What are Extraneous Variables?
- A variable that might effect the DV that is not the IV
- A variable that explains the relationship between the IV and DV but is not apart of the study
- Results in a false conclsuion
What may Extraneous Variables arise from?
- Participant variables
- E.g., Age, gender, sex, physical fitness, healthstatus
- Situational variables
- E.g., Temperature of testing room, wateravailability,
wind, time of day
- Experimenter variables
- E.g., Appearance and conduct of theresearcher
How do researchers Control for
Extraneous Variables?
- Can be controlled through the design of the study
- Examples: experimental setting, instructions to participants, experimenter-participant interactions, participant selection criteria, random assignment with a control group
- Held constant
- Can be controlled through statistical analysis
- ‘Control variables’
- Requires you to measure thevariable
What are Moderators?
- Variables that affect the strength of the relationship between IV/predictor & DV/criterion
- Usually categorical in nature
What are Mediators?
Variables that explain the relationship between IV & DV
- Accounts for the relationship between the IV/predictor and the DV/criterion
- Helps to think of mediator as the mechanism between IV/predictor & DV/criterion
