Descriptive statistics- summarize and describe the characteristics of a set of scores. Frequency distribution- shows how many participants received each score: shows certain characteristics of the data. Measures of variability- provide information about the spread of scores in a distribution. Range- difference between the highest and lowest score in a distribution. Deviation score- measures the distance between each core and the mean. Variance- the average of the squared deviation scores about the mean. Standard deviation- square root of the variance. Error variance- 80 percent of variance has factors that are random and beyond the control of the experimenter. Variance accounted for applies to experiments and correlational studies. The correlational research doesn"t involve manipulating variables but it involves measuring two or more variables and looking at if one variable changing is associated with the other. Pearson product-moment correlation coefficient- statistic that reflects the direction and strength of the relation between two variables.