Because of staffing decisions, managers of the Gibson-Marion Hotel are interested in the variability in the number of rooms occupied per day during a particular season of the year. A sample of days of operation shows a sample mean of rooms occupied per day and a sample standard deviation of rooms. Required:
a. What is the point estimate of the population variance?
b. Provide a 90% confidence interval estimate of the population variance.
c. Provide a 90% confidence interval estimate of the population standard deviation.

a)

b)

c)

Step-by-step explanation:

Assuming the following question: Because of staffing decisions, managers of the Gibson-Marimont Hotel are interested in  the variability in the number of rooms occupied per day during a particular season of the  year. A sample of 20 days of operation shows a sample mean of 290 rooms occupied per  day and a sample standard deviation of 30 rooms

Part a

For this case the best point of estimate for the population variance would be:

Part b

The confidence interval for the population variance is given by the following formula:

The degrees of freedom are given by:

Since the Confidence is 0.90 or 90%, the significance and , the critical values for this case are:

And replacing into the formula for the interval we got:

Part c

Now we just take square root on both sides of the interval and we got:

step-by-step explanation:

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