test 2 notes Flashcards
Reliability
Property or attribute of consistency in measurement for a test
Reliability Coefficient
Statistic that ranges from 0 to 1.0
Classical Test Theory
Variance of any score is due to “true” measurement plus error
True Score
Reflects a person’s true ability/attribute/trait that test is trying to measure
Measurement Error
Influence of any other variable that could change a “true” score, e.g., low test reliability
Error
Actual test score minus the true score.
Measurement Error Sources
Unsystematic errors and systematic errors
Unsystematic Errors
Not as serious, from random scores, item selection, test administration, and test scoring
Systematic Errors
More serious, poor content domain sampling, question on a social intro version test that actually measures general anxiety
Coefficient Alpha
Ranges from 0 to 1
Cronbach’s α
Mean of all possible split-half reliability coefficients for a given test. Shows correlation of scores with each other
Kuder-Richardson-20
Similar to α, but used when test responses are dichotomous (True/False)
Decisions About People
.90 to .95 Reliability Coefficient
Research Tests
.80 reliability coefficient
Tests that seem promising but need more development
.70 reliability coefficient