5.96 Income of working couples. A study of working couples measures the income X of the husband and the income Y of the wife in a large number of couples in which both partners are employed. Suppose that you knew the means and and the variances and of both variables in the population.
(a) Is it reasonable to take the mean of the total income to be ? Explain your answer.
(b) Is it reasonable to take the variance of the total income to be ? Explain your answer.