The Customer Help Center in Your Company Receives Calls from Customers

Multiple Choice

The customer help center in your company receives calls from customers who need help with some of the customized software solutions your company provides.Your company claims that the average waiting time is 7 minutes at the busiest time, from 8 a.m.to 10 a.m., Monday through Thursday.One of your main clients has recently complained that every time she calls during the busy hours, the waiting time exceeds 7 minutes.You conduct a statistical study to determine the average waiting time with a sample of 35 calls, for which you obtain an average waiting time of 8.15 minutes.Suppose that you can assume that waiting times are normally distributed.The sample standard deviation is 4.2 minutes.The null hypothesis is:

A) n $\neq$ 35
B) n = 35
C) $\mu$ = 7
D) $\mu$ $\neq$ 7
E) $\mu$ > 7