In grading eggs into small, medium and large, Margi farms packs the eggs that weigh more than 4.25 ounces in packages marked " large" and the eggs that weigh less than 2.45 ounces in packages marked " small" the remainder are packed in packages marked " medium". If a day's packaging contained 10.56% large and 4.01% small eggs, calculate the mean and the standard deviation of the weights of eggs ( Assume that the distribution egg weights is normal)