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Mean Average (Mathematics Lesson)

What Is the Mean Average?

The mean average (arithmetic mean, mean, or just average) is the sum of all numbers divided by the total amount of numbers.

How to Find the Mean Average

Question: What is the average of 86, 99, 98, 54, 35, and 48?

Step 1
Add all the numbers in set.
(86 + 99 + 98 + 54 + 35 + 48 = 420).

Step 2
Count the amount of numbers in the set.
(There are 6 in this set.)

Step 3
Divide the sum of the numbers (420) by the amount of numbers (6) to get your answer.
(420/6 = 70). The mean average is 70.

Interactive Widget
Here is an interactive widget to help you learn about averages.

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Note

MEAN IS THE MOST COMMON TYPE OF AVERAGE

Mean is the most common average, and it’s the one that people will think you’re talking about if you don’t specify which average you’re using.

A WEAKNESS OF MEAN AVERAGE

Mean average is useful when a central tendency or middle figure is needed, but its weakness is that is can be badly skewed by outliers. For example, it would be useful in measuring the average salary of a group of metal workers in a factory, but it would be less useful in measuring the average salary of everyone in the factory, because the factory owner’s and executives’ salaries would skew the mean figure. As a result, a senior but non-exectutive manager could find himself on a "below average" wage.

DISCUSSION POINT

Did you know that half the doctors in the world are below average?

(NB: They are compared to the other half of doctors but not compared to the rest of the population.)