## What is the mean value?

Knowing how to find the mean value can be quite helpful in daily life.

For example, the mean of the test score, the mean value of money spent for a year, etc.

The mean value is the total divided by the number of pieces (data).

For example, for the data (7,5,6), the total is 7+5+6=18, and the number of data is 3, so the mean is 18÷3=6.

## How to find the mean

Let's look at a more difficult specific example of calculating the mean.

For example:

Five students weigh 55 kg, 70 kg, 45 kg, 59 kg, and 51 kg, respectively.

What is the mean value?

To find the mean value, first, find the total weight as follows:

The total weight is 55+70+45+59+51=280kg.

The number of data (number of students) is 5.

The mean value is the total weight divided by the number of students, so the mean value is 280/5=56kg.

When you have a large amount of data (numbers), one way to easily and quickly represent the information in the data is to use the mean.

For example, in setting up the weight example mentioned earlier,

"What are the approximate weights of the five people?" and

you don't have to know the weight of each person, but you want to know one number.

One of the answers is the mean (in this case, 56 kg).

In this way, the "mean" comes into play where you want to represent many numbers simply with a single number.

Other representative values (median, mode) may be used instead of the mean, but the "mean" is the most famous.

## Formula to find the mean value

The mean value over n data (X1, X2, ⋯ , Xn) is the sum divided by the number, so the formula is

**(X1 + X2 + ⋯ + Xn) ÷ n**

, where n is the number of data.

For example, six students scored 80,100,52,52,72,70 on a math test. Find the mean of the test scores.

The mean of the test scores is calculated as follows:

The number of data is 6, so the mean value is:

= (80 + 100 + 52 + 52 + 72 + 70) **÷ 6**

**= 71**