So I am lost on this one. -- I have a sample that consists of 5 grades - best, better, average, worse, worst. The grades follow a normal distribution. If the sample size is 100, how do i determine the 'quantity' of each grade?

So I am lost on this one. -- I have a sample that consists of 5 grades - best, better, average, worse, worst. The grades follow a normal distribution. If the sample size is 100, how do i determine the 'quantity' of each grade?

I wonder how do you come up the statement the grades follow a normal distribution. How do you define grade? Is it based on the marks, you place it in 5 buckets of grade?

This is an incomplete question. You can say it is normally distributed without sequential evidence. It has no frequency of marks or grade distribution, without such figure n, r, p and/ standard deviation you can't find the solution to it either by calculation or normal distribution table. Thanks. Charls