The historical output by employees is a mean of 120 units per hour with a standard deviation of 28 units. A new employee is tested on 30 different random occasions and is found to have an output of 107 units per hour. Does this indicate that the new employee's output is significantly different from the population mean output?
For the following sample, what is the 95% confidence interval for the population mean, if the population variance is known to be 9: 25.6, 19.8, 22.3, 24.1, 18.7, 21, 20.5, 19.8, 22.7, 23.2, 21.8, 22(n=12)? What is the 99% confidence interval if the population variance is unknown?