The Average Weekly Earnings of Bus Drivers in a City $\mu$

Short Answer

The average weekly earnings of bus drivers in a city are $950 (that is $\mu$ ) with a standard deviation of $45 (that is $\sigma$ ). Assume that we select a random sample of 81 bus drivers.
a.Compute the standard error of the mean.
b.What is the probability that the sample mean will be greater than $960?
c.If the population of bus drivers consisted of 400 drivers, what would be the standard error of the mean?