Quiz: Chapter 8 Quiz Submit Q This Question: 1 pt 4 of 10 (3 complete) This Quiz

Question

Quiz: Chapter 8 Quiz Submit Q This Question: 1 pt 4 of 10 (3 complete) This Quiz: 10 pts poss Suppose a retailer claims that the average wait time for a customer on its support line is 179 seconds. A random sample of 50 customers had an average wait time of 171 seconds. Assume the population standard deviation for wait time is 55 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 dam? Select the correct choice below, and Round to two decimal places as needed.) I in the answer boxes to complete your choice. A Yes, because the retailer's claim is between the lower limit of seconds and the upper limit ofseconds for the mean wait time. B. No, because the retailer's claim is not between the lower limit of seconds and the upper limit o seconds for the mean wait time

Explanation / Answer

here std error of mean =std deviation/(n)1/2 =55/(50)1/2 =7.7782

for 95% CI ; z =1.96

therefore 95% confidence interval =sample mean -/+z *std error =171 -/+ 1.96*7.7782 =155.75 to 186.25

hnc eoption A) ......lower limit 155.75 and the upper limit of 186.25.

( Note if above does not work please try: 155.76 to 186.24

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