Question: IQ tests The Wechsler Adult Intelligence Scale (WAIS) is a common "IQ test" for adults. The distribution of WAIS scores for persons over 16 years of age is approximately Normal with mean 100 and standard deviation 15.
(a) What is the probability that a randomly chosen individual has a WAIS score of 105 or higher? Show your work.
(b) Find the mean and standard deviation of the sampling distribution of the average WAIS score x - for an SRS of 60 people.
(c) What is the probability that the average WAIS score of an SRS of 60 people is 105 or higher? Show your work.
(d) Would your answers to any of parts (a), (b), or (c) be affected if the distribution of WAIS scores in the adult population were distinctly non-Normal? Explain.