Skill: Find the mean

The mean is the equal-share value of a data set.

To find it:

1. Add all the data values.
2. Count how many values there are.
3. Divide the sum by the number of values.

Example

A student reads for these numbers of minutes over 5 days:

$$20,\ 15,\ 25,\ 30,\ 10$$

Step 1: Add the values.

$$20+15+25+30+10=100$$

Step 2: Count the values.

There are $5$ numbers.

Step 3: Divide the sum by the number of values.

$$\text{Mean}=\frac{100}{5}=20$$

The mean is 20 minutes.

This means that if the total reading time, $100$ minutes, were shared equally across the 5 days, each day would have $20$ minutes.