Part 1: The following data is the cost of 5 subject textbooks: Calculate the mean and standard deviation - to calculate the standard deviation complete the table - You can use either formula, so complete the 2 light gray columns OR the 2 blue columns Cost (Xi) X1 - X (X1 - X ) 2 OR Cost (Xi) ( xi ) 2 $65 $65 $69 $69 $82 $82 $76 $76 $73 $73 Sum = Sum = Sum = Mean: x = If you chose the gray columns finish completing the standard deviation using the formula: E(x1 - X) 2 n- 1