## LESSON: Histograms

### READ: Make a Histogram given a Frequency Table

## Make a Histogram given a Frequency Table

Frequency tables are a great way to record and organize data. Once you have created a frequency table, we can make a histogram to present a visual display of the information in the frequency table.

**What is a histogram?**

**A** *histogram***shows the frequency of data values on a graph. Like a frequency table, data is grouped in intervals of equal size that do not overlap. Like a bar graph, the height of each bar depicts the frequency of the data values. A histogram differs from a bar graph in that the vertical columns are drawn with no space in between them.**

Now let’s look at creating a histogram from a frequency table.

Example 1

Create a histogram using the results on the frequency table below.

Number of Hours Slept |
Tally |
Frequency |

5 | I | 1 |

6 | I I | 2 |

7 | I I I I | 4 |

8 | I I I | 3 |

9 | I I I | 3 |

10 | I I I | 3 |

11 | I I | 2 |

12 | I I | 2 |

To create a histogram:

1. Draw the horizontal and vertical axis.

2. Give the graph the title “Hours Slept Each Night.”

3. Label the horizontal axis “Hours.” List the intervals across the horizontal axis.

4. Label the vertical axis “Frequency.” Since the range in frequencies is not that great, label the axis by ones.

5. For each interval on the horizontal access, draw a vertical column to the appropriate frequency value. On a histogram, there is no space in between vertical columns.

Example 2

Create a histogram to display the data on the frequency table below.

Number of Minutes on the Computer |
Tally |
Frequency |

0 – 5 | I I I | 3 |

6 – 10 | I I | 2 |

11 – 15 | I I I | 3 |

16 – 20 | I I | 2 |

21 – 25 | I | 1 |

26 – 30 | I | 1 |

31 – 35 | I | 1 |

36 – 40 | I | 1 |

41 – 45 | I I | 2 |

46 – 50 | I | 1 |

51 – 55 | I | 1 |

56 – 60 | I I | 2 |

To create a histogram:

1. Draw the horizontal and vertical axis.

2. Give the graph the title “Minutes Spent on the Computer.”

3. Label the horizontal axis “Minutes.” List the intervals across the horizontal axis.

4. Title the vertical axis “Frequency.” Label the axis by halves (0.5).

5. For each interval on the horizontal access, draw a vertical column to the appropriate frequency value. Recall that on a histogram, there are no spaces in between vertical columns.