Which distribution should you use for this problem? (Enter your answer in the form z or tdf where df is the degrees of freedom.)

Question

A hospital is trying to cut down on emergency room wait times. It is interested in the amount of time patients must wait before being called back to be examined. An investigation committee randomly surveyed 70 patients. The sample mean was 1.5 hours with a sample standard deviation of 0.5 hours.

Which distribution should you use for this problem? (Enter your answer in the form z or t_df where df is the degrees of freedom.)

 

Answer 1

We should use the t-distribution because we don't know what the population standard deviation is.