PSY230H5 Lecture Notes - Lecture 3: Internal Consistency, Discriminant, Uncorrelated Random Variables
Document Summary
Relevance of this lecture: this lecture explains the relation between correlations and causality, this lecture explains the distinction between personality measures and personality constructs (validity). Internal consistency can be measured by assigning half of the items of a scale to one variable, and the other half to another variable, and then compute the correlation between the two variables (split-half reliability). Measuring the same items twice over a relatively brief period of time (e. g. , one week apart). Can be influenced by responses to previous items. Can be influenced by shared error variance (e. g. , something that happened that day: retest correlations: Can still be influenced by memory of previous response. The true score could have changed over time. A ruler is a valid measure of height. A scale is a valid measure of weight. Statistical definition: the correlation between variance in a measure and variance in the intended construct.
