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# How do I calculate the mean of a data set?

By Garret Patton on the 11th of June, 2012

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A mean is simply the average of the values included in the set of data. You simply add up all the numbers in the data set, and divide by how many numbers are in the data set.

The sum is divided by the count.

Ex: What is the Mean of the following set of data?

11, 3, 5, 6, 8, 10, 11

Divide the total by how many numbers there are in the set (there are 7) : 49 / 7

The Mean is 7

By Melissa-Anne Labranche on the 16th of January, 2013

## Calculate the mean for a frequency distribution

As you should know to calculate the mean it is not very hard, all we have to do is add up all the numbers and divide by however many numbers there are.

But, sometimes we may have a frequency table which shows how many times a number has come up. Lets work out the mean of our frequency distrubution from the following frequency table.

Score                 Frequency

1                             6

2                             4

3                             3

4                             4

5                             2

All we must do to work out the mean is write out the information in to a simple sum.

1+1+1+1+1+1 + 2+2+2+2 + 3+3+3 + 4+4+4+4 + 5+5

6 + 4 + 3 + 4 +5

Simple enough isn't it? We could go one step further and make it look simpler by  multiplying the score by the frequency, shown below:

(1 x 6) + (2 x 4) + (3 x 3) + (4 x 4) + (5 x 2)

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So now we can work out our mean, shown below:

6 + 8 + 9 + 16 + 10 = 2.23

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## Follow the links below to see how this topic has appeared in past exam papers

AQA Unit 1March 2011 (H) - Page 2, Question 2

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