5.76 How large a sample is needed? The changing probabilities you found in Exercise 5.74 are due to the fact that the standard deviation of the sample proportion p gets smaller as the sample size n increases. If the population proportion is p = 0.41, how large a sample is needed to reduce the standard deviation of to o5 = 0.005? (The 68-95-99.7 rule then says that about 95% of all samples will have within 0.01 of the true p.)