# Histograms review

## Histograms

A histogram displays numerical data by grouping data into "bins" of equal width. Each bin is plotted as a bar whose height corresponds to how many data points are in that bin.

Bins are also sometimes called "intervals", "classes", or "buckets".

## Reading a histogram

The heights of the bars tell us how many data points are in each bin.

For example, this histogram says that Leonard's patch has pumpkins whose mass is between and kilograms.

*Want to learn more about reading histograms? Check out this video.*

*Want to practice some more problems like this? Check out this exercise.*

## Creating a histogram

Below are the lengths (in meters) of Luiza's drives from the last time that she played golf.

Here's how to make a histogram of this data:

**Step 1:**Decide on the width of each bin. If we go from to using bins with a width of , we can fit all of the data in bins.

There is no strict rule on how many bins to use—we just avoid using too few or too many bins.

**Step 2:**Count how many data points fall in each bin.

Driving distance (in meters) | Data points | Number of drives |
---|---|---|

- | ||

- | ||

- | ||

- | ||

- |

**Step 3:**Scale the -axis from to using intervals of width . Label the -axis "driving distance (meters)".

**Step 4:**Scale the -axis up to —or something just past it—since that will be the highest bar.

**Step 5:**Draw a bar for each interval so its height matches the number of drives in that interval.

*Want to learn more about making histograms? Check out this video.*

*Want to try some problems like this? Check out this exercise.*