Calculating a mean estimate is simply finding the average number or amount in a series. A mean is often referred to as an estimate because it represents the average of a series of number or amounts and does not always come out as a whole number. There are many instances where estimating the mean is an important skill in life. In Baseball, it's used to calculate a player's batting average. In the business world, calculating the mean is used to figure out the average monthly sales income over the course of a year.
Things You'll Need
 Calculator
A Very Simple Formula

Add your numbers. For example, 13 + 14 + 18 + 22 + 36 + 42 + 99 + 2 = 246.

Count the numbers used in the range. In this case it's 8 numbers.

Divide the sum by the number of numbers given. Using this example, 246 divided by 8 equals 30.75, which is the mean estimate.
Tips & Warnings
 Using a calculator makes adding the numbers easier and reduces the chance of errors.
 Adding a long series of numbers can seem very tedious so you should always double check your math to make sure you have the correct result.