The marks of students in a statistics test are normally distributed with a mean of 62 and std of 8 marks. If 10% have grade A and 15% have failed,compute
(i) Cut-off grage A mark
(ii) The pass mark.
Look in the back of your statistics textbook for a table called something like “area under normal distribution” to find the proportion/probability and its Z score.
Insert the Z score, mean and standard deviation into the equation below and solve.
Z = (score-mean)/SD