2. 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. what is the mean of c?

$85,000

Step-by-step explanation:

Given : 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.

If  C denote the combined earnings for a randomly selected couple.

Then, the mean of C will be :-

Hence, the mean of C = $85,000

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

true? is that what you're asking or do you mean something else?