A worker at a landscape design center uses a machine to fill bags with potting soil. Assume that the quantity put in each bag follows the continuous uniform distribution with low and high filling weights of 6.4 pounds and 8.9 pounds, respectively. a. Calculate the expected value and the standard deviation of this distribution. (Do not round intermediate calculations. Round your "Expected value" to 2 decimal places and "Standard deviation" answer to 4 decimal places.)