The average of a set of numbers is also known as the arithmetic mean or average value. It’s simple to calculate. Read on to find out how to calculate the average of a set of numbers, and whether it’s always useful.

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Mathematics Tutors &amp; Teachers for Private Lessons

The average of two or more numbers is the sum of those numbers divided by the count, or how many numbers you want to average. It’s also known as the arithmetic mean.

What Is the Average?

The arithmetic mean isn’t the only average. Below are a few other types:

However, the arithmetic mean is usually the only kind referred to simply as average.

Is There More than One Kind of Average?

Here’s how to calculate the average of a sum of numbers:

Divide the sum by the number of values you just added

Say you want to find the average of five numbers: 7, 11, 15, 21, and 22. Going by the above formula, here’s how to do it.

Second, divide the sum by the number of values you just added:

How to Calculate the Average of a Set of Numbers

The average gives you an overall picture of a situation. Say you’re a coffee drinker who’s going to spend a weekend house-sitting for a friend who doesn’t drink coffee. You want to get a general idea of how much coffee you drink so you can buy enough beans to last you there.

In order to do this, you keep a record for the entire preceding week then add up the numbers.

Your average is 2.3 cups of coffee a day. Now you can plan accordingly to make sure you don’t run out of coffee during your stay.

Why is the Average Useful?

Certain situations or groups of numbers have a few wildly different values or outliers. These can skew the result if you calculate the average, giving you a misleading overall picture.

For instance, say you want an overall idea of the allowance each of the 20 students in your kid’s class gets. Ten of them get an allowance of $12 a week, eight get $15, whereas the remaining two get $75. Here’s how these two outliers will skew the whole equation.

Add all the allowances and divide by the number of students:

The average, 19.5, misrepresents the group. In this case, the median should be used instead.

When is the Average Misleading?

So there you have it: To measure the average or arithmetic mean, simply add up all the numbers, divide them by the number of numbers, and you’ve got your average.

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How to Calculate the Average of a Set of Numbers

What Is the Average?

Is There More than One Kind of Average?

How to Calculate the Average of a Set of Numbers

Why is the Average Useful?

When is the Average Misleading?

Conclusion