A college professor wants to use a normal distribution to analyze his students’ grades. He randomly selects 200 previous grades and organizes them in the following table. The mean is 67.75 and the standard deviation is 13. Does the frequency distribution support the hypothesis that students’ grades follow a normal distribution? Do a 5 % test.

Transcribed Image Text:

Grades <40 41-50 51-60 61-70 71-80 81-90 >90 Frequency 2 15 35 70 40 28 10