A survey of college students asks the participants "how many times did you drink alcohol in the past 60 days?" 20 students reported that they drank alcohol the following number of times:

1 3 6 0 3 10 12 1 1 5

7 10 1 2 2 20 3 4 4 4

a) Calculate the sample mean= 9.9

b) Calculate the standard error of the sample mean=

c) Calculate a 95% confidence interval

4. A researcher is interested in race differences in the amount of bail set for whites and nonwhites. They recorded the dollar amounts of bail for a random sample of 8 white and 8 nonwhite defendants. The data are shown below:

Whites Nonwhites

$600 $800

$200 $550

$150 $1,000

$250 $1,100

$250 $400

$200 $100

$300 $750

$650 $1,300

a) Test the null hypothesis of no race difference in the amount of bail ( = .05).

*Hint, this is a t ratio calculation.

b) Based on the result, should there be concern about the presence of racial disparity in bail setting?

5. A criminal justice researcher is interested in examining whether students attending three different high schools differ in terms of their sense of safety while at school. Sense of school safety is measured on a scale from 0 to 10 with 0 indicating the student never feels safe at school and 10 indicating the student always feels safe at school. The data below are from a random sample of students from each school:

School A School B School C

1 7 6

2 9 3

4 9 5

4 10 5

5 8 2

a) Perform an ANOVA calculation to test the null hypothesis of no difference in sense of safety at school. Use = .05.