Assume the average selling price for houses in a certain county is $294,000 with a standard deviation of $51,000. a) Determine the coefficient of variation. b) Caculate the z-score for a house that sells for $321,000. c) Using the Empirical Rule, determine the range of prices that includes 68% of the homes around the mean. a) Determine the coefficient of variation. CV = % (Round to one decimal place as needed.) b) Calculate the z-score for a house that sells for $321,000. Z= (Round to two decimal places as needed.) c) Using the Empirical Rule, determine the range of prices that includes 68% of the homes around the mean. upper bound x = $ lower bound x = $ (Round to the nearest dollar as needed.)