Suppose that 30 percent of the items in a large manufactured lot are of poor quality. Suppose also that a random sample of n items is to be taken from the lot, and let Qn denote the proportion of the items in the sample that are of poor quality. Find a value of n such that Pr(0.2 ≤ Qn ≤ 0.4) ≥ 0.75 by using (a) the Chebyshev inequality and (b) the tables of the binomial distribution at the end of this book.