Question

The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people. The sample mean is 8.2 minutes. There is a known standard deviation of 2.2 minutes. The population distribution is assumed to be normal. Which distribution should you use for this problem

Answer 1

The z-distribution should be used for this problem.

Explanation:

The population distribution is assumed to be normal. Which distribution to use?

If we have the standard deviation for the sample, we use the t-distribution.

If we use the standard deviation for the population, we use the z-distribution.

There is a known standard deviation of 2.2 minutes.

This means that 2.2 is the population standard deviation, and thus, the z-distribution should be used for this problem.