Suppose a retailer claims that the average wait time for a customer on its suppo

Question

Suppose a retailer claims that the average wait time for a customer on its support line is 187 seconds. A random sample of 42 customers had an average wait time of 176 seconds. Assume the population standard deviation for wait time is 51 seconds. Using a 95% confidence interval, does this sample support the retailer's claim? Using a 95%confidence interval, does this sample support the retailer's claim? Select the correct choice below, and fill in the answer boxes to complete your choice.

(Round to two decimal places as needed.)

A.Yes, because the retailer's claim is between the lower limit of seconds and the upper limit of seconds for the mean wait time.

B. No, because the retailer's claim is not between the lower limit of seconds and the upper limit of seconds for the mean wait time.

Explanation / Answer

Solution :-

In the question the right ans is

A.Yes, because the retailer's claim is between the lower limit 160.1 of seconds and the upper limit of 191.9 seconds for the mean wait time.

Calculation steps are Here,

so ,

Standard error of the mean = SEM = S/N = 7.869

t(, N-1) = 2.02

and Confidence interval = m +/- (t(, N-1)*SEM)
for lower bound CI = m-(t(, N-1)*SEM) = 176 - (2.02*7.869) =176-15895 =160.1

for upper bound CI =m+ (t(, N-1)*SEM) =176 + (2.02*7.869) =176+15895 =191.9

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