What type of procedure should we use, t or z? A company would like to estimate the average commute time of their employees to work. They take a random sample of 40 employees and ask them how long their commute is in minutes. The sample yields an average of 38 minutes and a standard deviation of 8 minutes. From this they would like to calculate a 95% confidence interval. This scenario should use a ___.A) One sample z procedure for a meanB) One sample t procedure for a meanC) A matched pairs t procedure for the mean difference

B) One sample t procedure for a mean

Step-by-step explanation:

Following are the conditions required to use the tests listed in the options:

1) One sample z procedure for a mean

This test is used when the value of population standard deviation is known and we are dealing with only one sample and its mean.

2) One sample t procedure for a mean

This test is used when the value of population standard deviation is unknown but value of sample standard deviation is know. In this case again we are dealing with 1 sample.

3) A matched pairs t procedure for the mean difference

This test is used when we deal with a sample but we consider two different readings from the sample at two different points in time to compare them to each other.

The information given in the above statement is:

A random sample of size = n = 40

Sample mean = u = 38

Sample Standard Deviation = s = 8

Since, the value of population standard deviation is unknown, value of sample standard deviation is known and we have to deal with only 1 sample, we will use One sample t-test procedure for the mean.

25% is the answer