3. Find P(84 x 89). (Round your answer to four decimal places.) 4. Consider an x distribution with standard deviation = 33.(a) If specifications for a research project require the standard error of the corresponding x distribution to be 3, how large does the sample size need to be? n =

(b) If specifications for a research project require the standard error of the corresponding x distribution to be 1, how large does the sample size need to be? n = 5. Suppose x has a distribution with = 13 and = 12. (a) If a random sample of size n = 49 is drawn, find x, x and P(13 x 15). (Round x to two decimal places and the probability to four decimal places.) x = x = P(13 x 15) = (b) If a random sample of size n = 67 is drawn, find x, x and P(13 x 15). (Round x to two decimal places and the probability to four decimal places.) x = x = P(13 x 15) =