Each patient at a hospital is asked to evaluate the service at the time of discharge. Recently, there have been several complaints that resident physicians and nurses on the surgical wing respond too slowly to the emergency calls of senior citizens compared to other patient groups. The administrator of the hospital asked the quality assurance department to investigate. After studying the problem, the quality assurance department collected the following sample information.
Senior Citizens:

Sample mean = 5.5 minutes
Standard deviation = 0.40 minutes
Sample size = 50
Other:
Sample mean = 5.3
Standard deviation = 0.30 minutes
Sample size = 100