Employment An employment agency requires all clients to take an aptitude test. They randomly selected 150 clients and recorded the amount of time each client took to complete the test. The average time needed to complete the test was 27.5 minutes with a standard deviation of 3.5 minutes.
a. What is the standard error of the mean?
b. Find the interval about the sample mean that reflects a 50% chance that the true mean lies within that interval.
c. Find the interval about the sample mean that has a 1% level of confidence.