Skill: Calculate mean, median, mode, and range

To find the mean, median, mode, and range, use the same data set and calculate each measure separately.

Suppose the data set is:

$$4,\ 7,\ 5,\ 7,\ 9,\ 3,\ 7$$

1. Mean

The mean is the total divided by the number of values.

Add the values:

$$4+7+5+7+9+3+7=42$$

There are $7$ values, so divide:

$$\text{Mean}=\frac{42}{7}=6$$

The mean is 6.

2. Median

The median is the middle value, so first put the data in order:

$$3,\ 4,\ 5,\ 7,\ 7,\ 7,\ 9$$

There are $7$ values. The middle value is the fourth value:

$$\text{Median}=7$$

The median is 7.

3. Mode

The mode is the value that appears most often.

The value $7$ appears three times, more than any other value.

$$\text{Mode}=7$$

The mode is 7.

4. Range

The range shows the spread of the data. Subtract the smallest value from the largest value:

$$\text{Range}=9-3=6$$

The range is 6.

Therefore, for this data set:

• Mean: $6$
• Median: $7$
• Mode: $7$
• Range: $6$

Always order the data before finding the median, and remember that a data set can have no mode or more than one mode.