Three Claims, Four Validities - Chapter 3
Variables vs. constants
Measured or manipulated
IMPORTANT: Dependent variables = measured, Independent variables =
Constants are controlled
From conceptual variable to operational definition
Broad statement to specific measure
Measured and Manipulated Variables
Measured variables are observed and recorded.
Manipulated variables are controlled.
Some variables can only be measured, not manipulated.
Some variables can be either manipulated or measured.
From Conceptual Variable to Operational Definition
Conceptual variables are common in psychology (anxiety; temperament).
Operational definitions help define abstract concepts.
Not all claims are based on research.
Frequency claims describe a particular rate or degree of a single variable.
Frequency claims involve only ONE MEASURED VARIABLE.
Example of Freq. Claim: 1 in 25 U.S teens attempt suicide.
Association claims argue that one level of a variable is likely to be associated with a
particular level of another variable.
Association claims involve at least TWO MEASURED VARIABLES.
Variables that are associated are correlated.
Example of Association Claim: Single people eat fewer vegetables.