A statistician analyzed data from 25 students to using the z test to obtain the probability of the mean time (45 minutes) it takes students to complete a midterm exam in a college in south dakota using a standard deviation which was obtained from studying students in the previous year's epidemiology class in SDSU. Assuming that the mean time it takes students to complete a midterm exam in South Dakota is normally distributed--although no one has ever bothered to calculate it, is the use of a z test in this scenario justified? Provide ONE reason to support your claim