# PSY201H1 Lecture Notes - Lecture 4: Xg Technology, Squared Deviations From The Mean, Variance

## Document Summary

Goal of central tendency: find the single most representative score of your data. Central tendency: a statistical measure to determine a single score that defines the center of distribution; there are three different methods for measuring central tendency. Mean: the sum of the scores ( x) divided by the total number of scores (n or n) the arithmetic average. Sample mean: m or: can be used as an estimate of the population mean. Used when we have more than one set of score the overall mean". The sample that holds a majority of the total percentage holds more say in the weighted mean. Finding the mean of a frequency distribution table. Calculating n from a frequency distribution table n = f. If the scores in a distribution are listed in order from smallest to largest, the median is the midpoint of the list. If there is no middle score" we find the average of the two middle scores.