Chapter 11, Problem DHGP

The Statistical Abstract of the United States reported information about the percentage of arrests of all drunk drivers according to age group. In the following table, the entry 3.7 in the first row means that in the entire United States, about 3.7% of all people arrested for drunk driving were in the age group 16-17 years. The Freemont County Sheriff’s Office obtained data about the number of drunk drivers arrested in each age group over the past several years. In the following table, the entry 8 in the first row means that eight people in the age group 16-17 years were arrested for drunk driving in Freemont County.

Distribution of Drunk-Driving Arrests by Age

Age	National Percentage	Number in Freemont County
16-17	3.7	8
18-24	18.9	35
25-29	12.9	23
30-34	10.3	19
35-39	8.5	12
40-44	7.9	14
45-49	8.0	16
50-54	7.9	13
55-59	6.8	10
60-64	5.7	9
65 and over	9.4	15
	100%	174

Use a chi-square test with 5% level of significance to test the claim that the age distribution of drunk drivers arrested in Freemont County is the same as the national age distribution of drunk drivers arrested.

State the null and alternate hypotheses.

Find the value of the chi-square test statistic from the sample.

Find the degrees of freedom and the P-value of the test statistic.

Decide whether you should reject or fail to reject the null hypothesis.

Interpret your conclusion in the context of the problem.

How could you gather data and conduct a similar test for the city or county in which you live? Explain.