problem-11.3

problem-11.3  A boxplot will show that the income data, like most income data, is heavily skewed.
> boxplot(income ~ race, data=female.inc)
    
An analysis of variance using oneway.test() would be inappropriate. However, the three population distributions appear to be roughly the same shape. The Kruskal-Wallis test then is appropriate.
> kruskal.test(income ~ race, data=female.inc)

        Kruskal-Wallis rank sum test

data:  income by race
Kruskal-Wallis chi-squared = 11.79, df = 2, p-value = 0.002748
    
The small p-value is not consistent with the assumption of equal mean wages for all three races represented in the data.