A hospital branch located in a commercial district of a city has developed an improved process for serving costumers during the early morning from 7:am to 9:00 am. The waiting time (defined as the...

A hospital branch located in a commercial district of a city has developed an improved process for serving costumers during the early morning from 7:am to 9:00 am. The waiting time (defined as the time costumer fall in line until he or she is finished with her/his transaction) of all costumers during this hour is recorded over a period of 1 week. A random sample of 20 costumers is selected, and the results are as follows:

5.21    4.35    4.02    5.43    3.77    4.34    4.54    3.90    5.10    6.05

5.46    6.29    4.79    2.45    3.69    5.15    4.20    5.10    3.12    1.38

At the 0.05 level of significance, is there evidence that the mean waiting time is less than 5 minutes?