PSY 350 Lecture 8: PSY 350 1-30-18
Document Summary
Calculate and interpret z-scores for a distribution of observed scores, using the mean and standard deviation. Describes where a particular observation falls, relative to others, in a distribution. Relative to the mean: is it higher or lower than the average. In terms of sd: how much higher or lower. Also makes it possible to compare different distributions on a common scale. Comes in handy when we want to look at two variables together. Zero = right at the mean: the value. The value of a z-score is the number of standard deviations between the mean and the original score. Z = +1. 5 = 1. 5 standard deviations above the mean. Z = -2. 0 = 2 standard deviations below the mean. ***remember that in a symmetric distribution, the mean, median, and mode fall close together. So about half the observations will fall below the mean, and about half will fall above.
