# Standard mean

• Mar 10th 2011, 03:31 AM
CaliforniaLove
Standard mean
The average weekly earnings of bus drivers in a city are \$950 (that is m) with a standard deviation of \$45 (that is s). 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?
• Mar 10th 2011, 03:35 AM
mr fantastic
Quote:

Originally Posted by CaliforniaLove
The average weekly earnings of bus drivers in a city are \$950 (that is m) with a standard deviation of \$45 (that is s). 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?

What have you tried? Where are you stuck? Surely your textbook or class notes have the necessary formula and an example to follow ....? (You will also find many questions like the ones you've posted in this subforum. Have you taken a look?).