Means, Averages, How to Calculate mean value, Basic Mathematics

There are many instances when it is important to know the average (mean) value of a set of
numbers. In sports we are interested in one‟s bowling average or batting average. In supply management we may want to know average demand for an item for a given time period, e.g., a month. We may also want to know the average demand for the entire year. Here is how to calculate these averages.

To calculate an average, follow these three steps:

Step 1. Add (total) all of the numbers in the set you want to average.

Step 2. Count how many numbers are in the set.

Step 3. Divide the total (sum) from Step 1 by the result of your count from Step 2.


When calculating the average over several time periods, do not average the average values for the time period! You must take the average of all the values in all of the time periods, following these steps.

Step 1. Find the total of all of the numbers in all of the sets you want to average.

Step 2. Determine the total number of numbers in all of the sets.

Step 3. Divide the total from Step 1 by the total number from Step 2.

Example,

Calculate the average of the following set of numbers: 126, 134, 155, 101, 144, 138, 151, 139

Step 1. 126 + 134 + 155 + 101 + 144 + 138 + 151 + 139 = 1, 088

Step 2. There are 8 numbers in the set. Step 3. 1,088 ÷ 8 = 136