How to Find the Mean
The mean is just the average of the numbers.
It is easy to calculate: Just add up all the numbers, then divide by how many numbers there are.
In other words it is the sum divided by the count.
Example 1:
What is the Mean of these numbers?
6, 11, 7
Add the numbers: 6 + 11 + 7 = 24
Divide by how many numbers (ie we added 3 numbers): 24 ÷
3 = 8
The Mean is 8
Why Does This Work?
It is because 6, 11 and 7 added together is the same as 3 lots of 8:
It is like you are "flattening out" the numbers
Example 2:
Look at these numbers:
3, 7, 5, 13, 20, 23, 39, 23, 40, 23, 14, 12, 56, 23, 29
The sum of these numbers is equal to 330 There are fifteen numbers.
The mean is equal to 330 ÷ 15 = 22
The mean of the above numbers is 22
Negative Numbers
How do you handle negative numbers? Adding a negative number is the same as subtracting the number (without the negative). For example 3 + (-2) = 3-2 = 1. So, knowing this, let us try an example: Example 3:
Find the mean of these numbers:
3, -7, 5, 13, -2
The sum of these numbers is 3-7+5+13-2 = 12 There are 5 numbers.
The mean is equal to 12 ÷ 5 = 2.4
The mean of the above numbers is 2.4
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