Suppose that the starting salaries of female CFO have a mean of $56,000 and a standard deviation of $12,000. The starting salaries of male CFO have a mean of $50,000 and a standard deviation of $10,000. A random sample of 50 female CFO’s and a random sample of 40 male CFO’s are selected.

Question

Suppose that the starting salaries of female CFO have a mean of $56,000 and a standard deviation of $12,000. The starting salaries of male CFO have a mean of $50,000 and a standard deviation of $10,000. A random sample of 50 female CFO’s and a random sample of 40 male CFO’s are selected.
Find

Find the expected value of the sample mean difference.
Find the standard error of the sample mean difference.
What is the probability that the sample mean salary of male CFO will not exceed that of the female CFO’s?

PsyDAG · Answer

Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√n

If only one SD is provided, you can use just that to determine SEdiff.

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability
related to the Z score.