Mean is one of the most common and valuable analytical statistics tools you can learn. It is a tool you use to calculate the average value of a set of numbers, which can help you understand and compare data.

If you are new to this concept, you might have questions like: how do you calculate mean? And what does it mean?

Don’t worry. In this guide, we will explore the concept of mean, how to find it, and some examples of how to use it in real life.

**What is Mean**?

The arithmetic mean is the sum of all the numbers divided by the number in the set. For example, if you have a set of five numbers: 2, 4, 6, 8, and 10, the mean is:

- Mean = (2 + 4 + 6 + 8 + 10) / 5
- Mean = 30 / 5
- Mean = 6

The mean is 6, meaning the average value of the numbers is 6. The mean can be considered a balance point or the centre of the data.

If the numbers are plotted on a number line, the mean is the point where the data is equally distributed on both sides.

**How to Calculate Mean?**

Calculating the mean of data is very easy if you follow the correct guide. To calculate the mean, you need to follow these steps:

- Add up all the numbers in the set. This is called the sum.
- Count how many numbers are in the set. This is called the size.
- Divide the sum by the size. This is the mean.

You can use this formula to find the mean of any set of numbers:

Mean = sum/size

**Practical Examples of Calculating Mean**

Here is an example of how to calculate the mean using this formula:

Find the mean of these numbers: 3, 5, 7, 9, and 11.

- Add up all the numbers: 3 + 5 + 7 + 9 + 11 = 35. This is the sum.
- Count how many numbers are in the set: 5. This is the size.
- Divide the sum by the size: 35 / 5 = 7. This is the mean.

The mean of these numbers is 7.

**Why is Mean Useful?**

Mean is helpful because it gives a simplified, easy way to summarize a set of numbers with one number. It can help you answer questions like:

- What is the average score in an examination?
- What is the average salary of a country?
- Also, what is the average temperature for a month?

Mean is also useful when comparing different sets of numbers and seeing how they differ. For example, you can use mean to compare the performance of two classes, the growth of two plants, or the speed of two cars.

You should note that the mean is not always the best measure of the data. Sometimes, the mean can be misleading or inaccurate, especially when the data has outliers or is skewed.

Outliers are extreme values that differ significantly from the rest of the data.

Skewed data is when the data is not symmetrical and has more values on one side than the other. In these cases, the mean can be affected by the outliers or the skewness and not reflect the true centre of the data.

**For Example**

Suppose you have a set of numbers: 1, 2, 3, 4, 5, and 100. The mean of these numbers is:

- Mean = (1 + 2 + 3 + 4 + 5 + 100) / 6
- Mean = 115 / 6
- Mean = 19.17

The mean is 19.17, much higher than most of the numbers in the set. This is because the outlier 100 is pulling the mean up and making it seem like the average value is higher than it is. In this case, the mean does not represent the data well.

In this case, a better measure of the data might be the median, the middle value of the data, when sorted in order. The median of these numbers is:

median = 3.5

The median is 3.5, which is closer to the majority of the numbers in the set. The median is not affected by the outlier 100 and reflects the true centre of the data better than the mean.

**Conclusion**

Mean is a handy statistical method for understanding and comparing data. It is the average value of a set of numbers, which can be calculated by adding up all the numbers and dividing by the number of numbers.

Mean is not always the best measure of the data, especially when the data has outliers or is skewed. In these cases, it is advisable to use other data measures, such as the median, to get a more accurate and reliable picture of the data.

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