Statistics

To find a missing number when the average (mean) of all the numbers in a set is given, plug into the arithmeticmean formula all the numbers you know which include the average, the sum of the other numbers, and the number of terms. Then, use algebra to find the missing number.
The average of five numbers is 26. Four of the numbers are 12, 90, 26, and 10. What is the fifth number? To solve the problem algebraically, let x=the missing number. Set up the artithmeticmean formula, then solve for x:
130 = 62+x 68 = x The fifth number is 68.
