Frequency density = |
frequency |

width of class interval |

**Example**

A company has 725 workers.

The following table shows the distribution of weekly wages.

Weekly Wages (£) | frequency (f) |
---|---|

0 ≤ w < 200 | 200 |

200 ≤ w < 300 | 200 |

300 ≤ w < 350 | 125 |

350 ≤ w < 500 | 150 |

500 ≤ w < 600 | 50 |

Total | 725 |

Work out the Frequency Densities for this distribution.

**Answer**

We extend the table with two new columns to show class width and Frequency density.

Using the formula below, we work out the Frequency density for each class width.

Frequency density = |
frequency |

width of class interval |

Weekly Wages (£) | frequency (f) | Class width | Frequency density |
---|---|---|---|

0 ≤ w < 200 | 200 | 200 | 200 ÷ 200 = 1 |

200 ≤ w < 300 | 200 | 100 | 200 ÷ 100 = 2 |

300 ≤ w < 350 | 125 | 50 | 125 ÷ 50 = 2.5 |

350 ≤ w < 500 | 150 | 150 | 150 ÷ 150 = 1 |

500 ≤ w < 600 | 50 | 100 | 50 ÷ 100 = 0.5 |

Total | 725 |