How to calculate the mean

 To calculate the mean (average) of a set of numbers, follow these steps:

1. 
2. Add up all the numbers in the set.
3. Count how many numbers are in the set.
4. Divide the sum from step 1 by the count from step 2.

The formula for calculating the mean (μ) is:

μ = (Sum of all numbers) / (Number of numbers)

For example, if you want to find the mean of the numbers 5, 10, 15, and 20:

1. Sum of all numbers = 5 + 10 + 15 + 20 = 50
2. Number of numbers = 4
3. Mean (average) = 50 / 4 = 12.5

So, the mean of these numbers is 12.5.