SOLUTION: the instructor of Biostatistics course is assumed that the distribution of marks of students for the course is normally distributed with mean 70 and standard deviation of 15. he wa

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Question 939420: the instructor of Biostatistics course is assumed that the distribution of marks of students for the course is normally distributed with mean 70 and standard deviation of 15. he wants to give grade A for the maximum 5% of students, grade B for 25% students, and grade C for 60%, grade for the remaining. Find the cut mark for all grades?
please I need the answer after 20 minutes as soon as you get the question. I think it is easy for you.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
mean 70 and standard deviation of 15
z+=+blue%28X+-+mu%29%2Fblue%28sigma%29
15invNorm(.95) + 70 = Xa = 95, cut off for A
15invNorm( .70) + 70 = Xb = 78 cut off for B
15invNorm(.10) + 70 = Xc = 51 cut off for C