14.3: What are the mean and standard deviation of his total weekly​ salaries?

Question

An employer pays a mean salary for a​ 5-day workweek of ​$1050 with a standard deviation of ​$136. On the​ weekends, his salary expenses have a mean of ​$350 with a standard deviation of ​$60. What are the mean and standard deviation of his total weekly​ salaries?

The mean of his total weekly salaries is ​$____________.

​(Round to the nearest integer as​ needed.)

Answer 1

mean = (5/7 * 1050 + 2/7 * 350 = 850

sum (5/7 * SD1 + 2/7 * SD2) = sqrt( 25/49 * VAR1 + 4/49 * VAR2) = sqrt(25/48 * 136^2 + 4/49 * 60^2) = 116.8 ~ 117