# PSYB01H3 Chapter 5: Chapter 5 notes

## Document Summary

A reliable measure does not fluctuate from one reading to the next. : consistency or stability of a measure of behaviour does fluctuate, there is error in the measurement device. Any measure you make comprises two components (1) a true score, which is the real score of the variable, and (2) measurement error. Reliability is most likely achieved when researchers use careful measurement procedures. We can"t directly observe the true score and error of an actual score on the measure. But we can assess the stability of measures using correlation coefficients. A correlation coefficient is a number that tells us how strongly two variables are related to each other. Most common correlation coefficient when discussing reliability is the pearson product-moment correlation coefficient. Pearson correlation coefficient (symbolized as r) can range from 0. 00 to +1. 00 and 0. 00 to -1. 00. 0. 00 tells us that the two variables are not related at all.