# Mean Deviation

• If x1, x2, ....... xn are the n-values of x, then mean deviation = \tt \frac{\sum_{i = 1}^{n}|x_i - M|}{n}
where M = Mean (or) Median (or) Mode
• If x1, x2, ....... xn are the n-values of x and its corresponding frequencies are f1, f2, ....... fn. Then mean Deviation \tt \frac{\sum_{i = 1}^{n} f_i |x_i - M|}{n}
Where N = Σ fi                 M = Mean (or) Median (or) Mode
• Coefficient of Mean Deviation = \tt \frac{Mean \ deviation}{M}
where M = Mean (or) Median (or) Mode

### View the Topic in this video From 29:25 To 53:48

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1. Mean deviation for ungrouped data

M.D.(\overline{x})=\frac{\sum|x_{i}-\overline{x}|}{n}, \ \ \ M.D.(M) = \frac{\sum|x_{i}-M|}{n}

2. Mean deviation for grouped data

M.D.(\overline{x})=\frac{\sum f_{i}|x_{i}-\overline{x}|}{N}, \ \ \ M.D.(M) = \frac{\sum f_{i}|x_{i}-M|}{N}, where N=\sum f_i