Senior managment of a consulting firm is concerned about a growing decline in the firm's weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviweing the records of all the firms full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours respectivily. Three questions to answer
1.Construct a 95% confidence interval for the standard deviation of the number of hours this firms employees spend on work related activities in a typical week. Need lower and upper limit rounded to 1 decimal place.
2. Construct a 99% confidence interval for the standard deviation of the number of hours this firms employees spend on work related activities in a typical week. Need lower and upper limit rounded to 1 decimal place.
3. Construct a 90% confidence interval for the standard deviation of the number of hours this firms employees spend on work related activities in a typical week. Need lower and upper limit rounded to 1 decimal place.