The customer expectation when phoning a customer service line isthat the average amount of time from completion of dialing untilthey hear the message indicating the time in queue is equal to 55.0seconds (less than a minute was the response from customerssurveyed, so the standard was established at 10% less than aminute).  

You decide to randomly sample at 20 times from 11:30am until9:30pm on 2 days to determine what the actual averageis.  The actual data was as follows:

54.1, 53.3, 56.1, 55.7, 54.0, 54.1, 54.5, 57.1, 55.2, 53.8,54.1,54.1, 56.1, 55.0, 55.9, 56.0 ,54.9, 54.3, 53.9, 55.0

What is a 95% confidence interval for the true mean callcompletion time?

What is the 95% confidence interval on the standarddeviation

The customer expectation when phoning a customer service line isthat the average amount of time from completion of dialing untilthey hear the message indicating the time in queue is equal to 55.0seconds (less than a minute was the response from customerssurveyed, so the standard was established at 10% less than aminute).  

You decide to randomly sample at 20 times from 11:30am until9:30pm on 2 days to determine what the actual averageis.  The actual data was as follows:

54.1, 53.3, 56.1, 55.7, 54.0, 54.1, 54.5, 57.1, 55.2, 53.8,54.1,54.1, 56.1, 55.0, 55.9, 56.0 ,54.9, 54.3, 53.9, 55.0

What is a 95% confidence interval for the true mean callcompletion time?

What is the 95% confidence interval on the standarddeviation