When Should You Use Mean, Median, or Mode: A Guide for Year 7 Students

In statistics, mean, median, and mode are ways to find the center of a group of numbers. They help us make sense of data. Let's break down when to use each of them.

1. Mean

• What it is: The mean is just the average of a group of numbers. To find it, you add all the numbers together and then divide by how many numbers there are.

• When to use it: Use the mean when the numbers are balanced and don’t have any weirdly high or low values.

  For example, if you have these numbers: 3, 5, 7, 8, and 10, here’s how you find the mean:

  1. Add them up: 3 + 5 + 7 + 8 + 10 = 33

  2. Divide by the number of values (which is 5):

     $$\text{Mean} = \frac{33}{5} = 6.6$$

2. Median

• What it is: The median is the middle number when you line up all the numbers in order. If there are two middle numbers, you find the average of those two.

• When to use it: Use the median when your numbers have some really high or low values, which are called outliers.

  For example, in the numbers: 2, 5, 7, 50, and 100, here’s how to find the median:

  1. Line them up: 2, 5, 7, 50, 100.
  2. The middle number is 7.

If you had an even number of values, like: 2, 5, 7, and 10, the two middle numbers would be 5 and 7, so you would do:

$$\text{Median} = \frac{(5 + 7)}{2} = 6$$

3. Mode

• What it is: The mode is the number that shows up the most in a group of numbers.

• When to use it: Use the mode when you want to find the most common number, especially when looking at categories.

  For example, in the numbers: 1, 2, 2, 3, and 4, the mode is 2 because it appears two times.

Summary

• Use Mean when your numbers are spread out evenly.
• Use Median when there are outliers or if the data is uneven.
• Use Mode to find the most common number or category.

Learning about mean, median, and mode will help you understand and analyze data better!