Answer:
0.004 is the probability that the mean salary of the sample is less than $57,500.
Explanation:
We are given the following information in the question:
Mean, μ = $60,500
Standard Deviation, σ = $6,400
Sample size, n = 32
Formula:
Standard error due to sampling =

P(mean salary of the sample is less than $57,500)
Calculation the value from standard normal z table, we have,
0.004 is the probability that the mean salary of the sample is less than $57,500.