An employer pays a mean salary for a 5day work week of 1200

An employer pays a mean salary for a 5-day work week of $1200 with a standard deviation of $128. On the weekends, his salary expenses have a mean of $400 with a standard deviation of $50. What is the mean and standard deviation of his total weekly salaries?

Solution

The mean is simply the sum of the means,

u(total) = u1 + u2 = 1200 + 400 = $1600 [ANSWER]

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The standard deviation of the total is given by

sigma(total) = sqrt(sigma1^2 + sigma2^2)

= sqrt(128^2 + 50^2)

= 137.4190671 [ANSWER]