Question

Calculate mean deviation from mean from the following data using direct method:

2, 4, 7, 8, 9

Answer 1

Direct Method

$\begin{array}{cc}\text{X}& \overline{X}=6\\ & |D|=|X-\overline{X}|\\ 2& 4\\ 4& 2\\ 7& 1\\ 8& 2\\ 9& 3\\ \sum X=30& \sum |D|=12\\ N=5& \end{array}$

$\overline{X}=\frac{\sum X}{N}=\frac{30}{5}=6$

$M.D_{\overline{X}}=\frac{\sum |D|}{N}=\frac{12}{5}=2.4$