If 95% of certain high-performance radial tires last at least 30,000 miles, find the mean and the standard deviation of the distribution of the number of these tires, among 20 selected at random, that last at least 30,000 miles, using (a) A table of binomial distributions, the formula which defines , and the computing formula for ????2. (b) the special formulas for the mean and the variance of a binomial distribution.