For the normal distribution described in given Exercise, what tax preparation fee would have been exceeded by 90% of the tax preparation customers?
Exercise
In 1999, the average charge for tax preparation by H&R Block, Inc. was $84.57. Assuming a normal distribution and a standard deviation of , what proportion of H&R Block's tax preparation fees were
a. more than $84.57?
b. between $64.57 and $104.57?
c. between $74.57 and $94.57?
d. more than $104.57?