Tutorial 5 - Applications of the Standard Normal Distribution The average hourly earnings of student tutors are R20 with a standard deviation of RIO.
Assume the hourly earnings of tutors are normally distributed.
a) If a tutor is selected at random what is the probability that he she earus
between R20 and R30 per hour for tutoring,
b) What is the probability that a tutor earns between Ris and R25 per hour?
c) What is the cut off hourly earnings to be in the top 10 percent?
d) Suppose there are 20 tutors in the sample studied, how many earn at least R25
per hour?
ident
ment​