## The Lesson

We can find the range of a set of numbers presented in a frequency table.## How to Find the Range from a Frequency Table

Finding the range from a frequency table is easy.## Question

The frequency table below shows the test scores for a class of students. What is the range of the test scores?## Step-by-Step:

# 1

Make sure the entries in the

**Score**column are in numerical order. In our example, the entries are in numerical order.# 2

Find the lowest entry in the

In our example, the lowest entry is 5. The lowest test score is 5.

**Score**column (with a**Frequency**greater than 0).In our example, the lowest entry is 5. The lowest test score is 5.

# 3

Find the highest entry in the

In our example, the highest entry is 10. The highest test score is 10.

**Score**column (with a**Frequency**greater than 0).In our example, the highest entry is 10. The highest test score is 10.

# 3

Subtract the lowest number (5) from the highest number (10).

10 − 5 = 5

## Answer:

The range of the test scores is 5.## Beware

## Make Sure the Numbers Are in Order

Make sure the numbers in the left most column are in order.**Don't forget:**The whole row, not just that in the first column, needs to be rearranged. Each number in the

**Frequency**column corresponds to the

**Number**to its left.

## Careful of 0 Frequencies

What is the range of the frequency table below?It is tempting to think that it is:

Range = 4 − 1 = 3

However, **Number**1 and 4 have a

**Frequency**of 0. That means there is actually no 1 and 4 in the set of numbers. Just ignore any row with a

**Frequency**of 0. The true range is:

Range = 3 − 2 = 1