Section 28.4

Exercise Set C: 2, 3, 5, 6, 7

Review Exercises (page 541): 3

Also:

In a study of the relationship between laterality of hand and laterality of eye, 413 subjects were classified according to these two characteristics. The results are in the following table

Test the null hypothesis that the laterality of hand and laterality of eye are independent.

Answer:

Using a chi-square test for independence, we find a test statistic of $\chi^2 = 4.0205$. Using a chi-square distribution with 4 degrees of freedom, the p-value is 0.4032. Thus there is no evidence against the hypothesis that laterality of hand and laterality of eye are independent.

Answer for Review Exercise # 3:

Using a chi-square test for independence, we find a test statistic of $\chi^2 = 14.2415$. Using a chi-square distribution with 4 degrees of freedom, the p-value is 0.006563. Thus there is strong evidence against the null hypothesis of independence of marital status and employment status.

Note: The warning message in R stating that the approximation may be incorrect is due to one of the expected frequencies being less than 5. Since the expected frequency in question is 3.86, and all of the other expected frequencies are well above 5, there is no need for concern with this warning message.