In a given population of two-earner male/female couples, male earnings have a mean of $40,000 per year and a standard deviation of $12.000. Female earnings have a mean of $45.000 per year and a standard deviation of $18.000. The correlation between male and female earnings for a couple is 0.80. Let C denote the combined earnings for a randomly selected couple.
(a) What is the mean of C?
(b) What is the covariance between male and female earnings?
(c) What is the standard deviation of C?
(d) Convert the answers to (a) through (c) from U.S. dollars ($) to euros (€).