Question: An electronics manufacturer has changed some of its welders from a straight salary to a piece rate method of compensation. The shop foreman has been asked to estimate the mean weekly output per employee under the new method. Below are the numbers of units produced in one week by each employee under this method:

Required: (a) Use the above data to construct a 99 percent confidence interval for mean output per employee.

(b) State any assumptions necessary for part (a) above.