Question

A group of researchers want to determine if incidents of drunk driving are equally likely to occur on different days of the week (f_e = 0.143). They collect data on drunk driving arrests and calculate frequencies for each day of the week. They collected data from 406 incidents overall. They observed the following frequencies: Sunday (24), Monday (59), Tuesday (46), Wednesday (37), Thursday (50), Friday (92), Saturday (98). Use a one-variable chi-square analysis (where α = .001) to determine if there are significant differences in drunk driving arrests by day of the week.

       4.      List your χ² test statistic

       5.      List your critical χ² value(s)

6.      Are there statistically significant differences in drunk driving arrests by day of the week? (Yes/No)

Answer 1

Ans:

	Observed(fo)	Expected(fe)	(fo-fe)^2/fe
Sunday	24	58	19.931
Monday	59	58	0.017
Tuesday	46	58	2.483
Wednesday	37	58	7.603
Thursday	50	58	1.103
Friday	92	58	19.931
Saturday	98	58	27.586
Total	406	406	78.655

4)Test statistic:

Chi square=78.655

df=7-1=6

5)critical chi square value=CHIINV(0.001,6)=22.458

6)As,Chi square test statistic is greater than critical chi square,we reject the null hypothesis.

Yes,there is sufficient evidence to conclude that there are statistically significant differences in drunk driving arrests by day of the week.