Question: Given a standard, interval-level IQ test ( \(\mu \) = 100 and \(\sigma \) = 15), and assuming that intelligence is normally distributed, answer the following questions.

a. If anyone with an IQ greater than 135 is considered a genius, what percentage of people in the world should be geniuses?

b. If Desdemona's IQ score is 67, what is her score as a percentile rank?

c. Buffy was told that her IQ score, as a percentile rank, was a 67. What is her IQ score?

d. Skip is exactly of average IQ and realizes that he needs a life partner who is smarter than he is. However, he realizes that someone who is too smart may—how shall I phrase this delicately?—find him a little "dull." Thus, he decides that his eligible pool of life partners consists of people who are from 10 to 25 IQ points smarter than he is. What percentage of people in the world, purely on the basis

e. You want to do a study that involves per; whose IQs are in the "normal" range, from 70 to 130. How many people must you screen with IQ tests in order to find a sample of 50 people with IQs in this range?