Weeks 2 & 3 Flashcards
Independent Variable
“cause,” controlled, x-axis.
Depedent Variable
“effect,” measured, y-axis.
Random Sample
When everyone in a target population has equal chance of being in the study.
Convenience Sample
Selecting people for the study who are easy and ready to recruit.
Theoretical Definition
What we think the concept is, broad, but straight forward. Ex: defining happiness.
Operational Definition
Defining the variable in terms of operations we will perform to measure it or manipulate it. More specific. (Ex: Number of times somebody smiles in a day).
If two variables correlate, what are three possible cause and effect relationships between them?
IV causes DV
DV causes IV (reverse causation)
Another variable affecting IV and/or DV (third variable)
Three conditions to prove cause and effect
association, temporal precedence, rule out alternative explanations.
Association
The cause and effect must correlate.
Temporal Precedence
Cause must precede the effect (directionality).
Ruling out alternative explanations
There should be no other plausible causes of the effect. (Third variable problem).
Manipulation
Participants forced to undergo one procedure or another. Controls extraneous variables.
Random Assignment
Everyone participating has an equal chance of being in every condition - removes potential third variable as all groups are on average the same before IV.
Internal Validity
The extent to which the relation between the operationally defined IV and operational defined DV is casual. Only high in experiments.
External Validity
The extent to which the relationship discovered between the conceptual IV and conceptual DV truly exists in desired “real-world” group. Higher for survey/correlational research.