chapter 4: identifying scientific variables Flashcards
variable
value or characteristic that can change or vary from one person to another, or from one situation to another
construct
a conceptual variable that is known to exist by cannot be directly observed (measured)
Often is a central component to a theory
Must identify external factors of the construct in order to measure/observe it
operational definition
external factor of construct
observable behavior or event that is presumed to reflect the construct itself and how it will be measured
continuous variables
measured along a continuum
Can be measured in whole units or fractional units
Measured at any place beyond the decimal point
Quantitative
ex// duration of drug abuse in years, core (0% - 100%) on an exam
discrete variables
measured in whole units or categories that are not distributed along a continuum
Quantitative or qualitative
ex// gender, seasons, number of dreams recalled, number of errors, ranking of favorite foods, ratings of satisfaction, body type
nominal
a number is assigned to represent something or someone
no order, no difference, no ratio
ex// seasons, gender
ordinal
convey order or rank, does not convey distance
order but no difference or ratio
ex// rankings, grade level
ratio
equidistant and true zero
order, difference, and ratio
ex// length, height, weight
interval
equidistant scales but no true zero
order and difference, no ratio
test-retest reliability
extent to which a measure or observation is consistent or stable at two points in time
time 1 vs time 2
ex// people get consistent scores every time they take a test
internal consistency
type of reliability
extent to which multiple items used to measure the same variable are related
item 1 vs item 2
ex// people give consistent scores on every item of a questionnaire
interrater reliability
extent to which two or more raters of the same behavior are in agreement with what they observed
rater 1 vs rater 2
ex// two coders’ ratings of a set of targets are consistent with each other
measurments of reliability
correlation, cronbach’s alpha, kappa
construct validity
extent to which a measurment for a variable/construct is actually measuring that variable/construct
subjective ways to assess validty
face validity
content validity = items or contents of a measure adequately rep all of the features of the construct being measured
