STANDARD NORMAL DEVIATION PROBLEM

Question

The course convenor for MAM1000 has decided to offer extra lessons to the students who score in the bottom 2% for the class test. The class average is 65% with a standard deviation of 8%. What is the cut off mark for students to be accepted into the extra lessons? Please help on this question

Answer 1

z = (x - mean)/SD

where x = score , mean = 0.65 SD = 0.8

find z-score for 2nd percentile = -2.05

-2.05 = (x - 0.65)/0.08

x = 0.486

or 48.6%