Question

An instructor in a large lecture class found at the end of the semester that total points scored by students in his class was approximately Normal with mean 530 and standard deviation 80. If 10% of the class are to receive A's (he grades on a curve), what is the lowest number of points for a student to earn an A?

A. 632
B. 610
C. 428

Answer 1

Here is how to find the answer:

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.10) and its Z score and insert the values into the above equation to find the Raw score.

Answer 2

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