The coefficient of mean deviation can be calculated by dividing the value of the mean absolute deviation by the mean of the data.

**Coefficient of Mean Deviation = Mean Absolute Deviation/Mean.**

**Formula for Coefficient of Mean Absolute Deviation:**

The value of the coefficient can be calculated using the formula,

Coefficient of Mean Deviation = Mean Absolute Deviation/Mean.

The Mean Absolute Deviation is given by the formula,

Mean Absolute Deviation = ∑|*x _{i}* –

**X̄**|/n.

**Example 1:**

Consider the set of data: 3, 3, 6, 7, 8, 9, 13.

Here, we have 7 data points therefore the value of n is 7. We first calculate the value of the mean for the given set of data values.

Mean = (3+ 3+ 6+ 7+ 8+ 9+ 13)/7 = 49/7 = 7.

We now calculate the value of the Mean Absolute Deviation as follows,

x _{i} | x – _{i}X̄ = x – 7_{i} | |x – _{i}X̄| |

3 | -4 | 4 |

3 | -4 | 4 |

6 | -1 | 1 |

7 | 0 | 0 |

8 | 1 | 1 |

9 | 2 | 2 |

13 | 6 | 6 |

∑|x – _{i}X̄| = 18 |

Mean Absolute Deviation = ∑|*x _{i}* –

**X̄**|/n = 18/7 = 2.5714.

We now calculate the value of the coeffcient of mean deviation as follows,

Coefficient of Mean Deviation = Mean Absolute Deviation/Mean = 2.5714/7 = 0.3673.

**Example 2:**

Consider the following set of data: 16, 39, 45, 46, 49, 99.

Mean = (16+ 39 + 45+ 46+ 49 + 99)/6 = 49.

x _{i} | x – _{i}X̄ = x – 49_{i} | |x – _{i}X̄| |

16 | -33 | 33 |

39 | -10 | 10 |

45 | -4 | 4 |

46 | -3 | 3 |

49 | 0 | 0 |

99 | 50 | 50 |

∑|x – _{i}X̄| = 100 |

Mean Absolute Deviation = 110/6 = 16.6667

Coefficient of Mean Deviation = Mean Absolute Deviation/Mean = 16.6667/49 = 0.3401.