Random sample of patrol officers, each scored 1-5 on a cynicism scale Sample 1 (n=10) Officer Score Mean Diff. Sq. 1 3 2.9 .1 .01 2 3 2.9 .1 .01 3 3 2.9 .1 .01 4 3 2.9 .1 .01 5 3 2.9 .1 .01 6 3 2.9 .1 .01 7 3 2.9 .1 .01 8 1 2.9 -1.9 3.61 9 2 2.9 -.9 .81 5 2.9 2.1 4.41 ------------------------------------------------- Sum 8.90 Variance (sum of squares / n-1) s2 .99 Standard deviation (sq. root of variance) s .99

Depicting the distribution of continuous variables: the histogram Distributions depict the frequency (number of cases) at each value of a variable. Here there is one variable: age, measured on a scale of 20-33. A case is a single unit that “contains” all the variables of interest. Here each student is a case Frequency means the number of cases – students – at a single value of a variable. Frequencies are always on the Y axis Values of the variable are always on the X axis Trend line Y - axis How many at each value/score Value or score of variable X - axis What is the area under the trend line “made up of”? Cases, meaning students (arranged by age)

Depicting distribution of a categorical variable: the bar graph Distributions depict the frequency (number of cases) at each value of a variable. Here there is one variable with two values: gender (M/F). A case is a single unit that “contains” all the variables of interest. Here each student is a case Frequency means the number of cases – students – at a single value of a variable. Frequencies are always on the Y axis Values of the variable are always on the X axis N = 32 n=17 n=15 Y - axis How many at each value/score Value or score of variable X - axis Bars are “made up of” cases. Here that means students, arranged by the variable gender Distributions illustrate how cases cluster or spread out according to the value or score of the variable. Here the proportions of men and women seem about equal.