The probability density function of the weight of packages delivered by a post office is f(x) a) Determine the mean and variance of weight. Meani pounds (Round the answer to 2 decimal places.) pounds2 (Round the answer to 1 decimal place.) Variance = i b) If the shipping cost is $2.50 per pound, what is the average shipping cost of a package? $ i answer to 1 decimal place.) c) Determine the probability that the weight of a package exceeds 50 pounds. (Round the answer to 5 decimal places.) 70 69x² for 1