A histogram is a lot more than a bar chart! In a histogram, the area of the bar, NOT its height, is proportional to frequency. Bars do not have to be of equal width. The height of each bar is called the frequency density.

## Software/Applets used on this page

## Glossary

### density

the ratio of the mass of an object to its volume

### frequency

Of a function: the rate of repetition of a periodic function.

In statistics: the number of occurances of a value

In statistics: the number of occurances of a value

### frequency density

The frequency density of a frequency distribution is given by

(class frequency)/(class width).

(class frequency)/(class width).

### histogram

A statistical diagram for continuous data similar to a bar chart but where the area of each bar is proportional to the frequency.

### union

The union of two sets A and B is the set containing all the elements of A and B.

## This question appears in the following syllabi:

Syllabus | Module | Section | Topic | Exam Year |
---|---|---|---|---|

GCSE Higher (UK) | Statistics | Displaying data | Histograms | - |

Universal (all site questions) | D | Displaying data | Histograms | - |

CBSE IX (India) | Statistics | Displaying Data | Histograms | - |

Edexcel GCSE (9-1) Higher (UK) | S: Statistics | S3: Grouped Data, Histograms and Cumulative Frequency | Histograms | - |

OCR GCSE (9-1) Higher (UK) | 12: Statistics | 12.02b: Grouped Data | Histograms | - |

AQA GCSE (9-1) Higher (UK) | S: Statistics | S3: Grouped Data, Histograms and Cumulative Frequency | Histograms | - |

CIE IGCSE (9-1) Maths (0626 UK) | 9 Statistics | B9.4 Graphical Representations | Histograms | - |

Edexcel AS/A2 Maths 2017 | Statistics | Data Presentation and Interpretation | Histograms | - |

Edexcel AS Maths 2017 | Statistics | Data Presentation and Interpretation | Histograms | - |

AQA AS Maths 2017 | Statistics | Data Presentation and Interpretation | Histograms | - |

OCR AS Maths 2017 | Statistics | Working with Data | Histograms | - |

OCR MEI AS Maths 2017 | Statistics | Working with Data | Histograms | - |

AQA AS/A2 Maths 2017 | Statistics | Data Presentation and Interpretation | Histograms | - |