Question

The following table gives height of certain persons:

Height (inches)	57	59	61	63	65	67	69	71	73
Number of Persons	1	3	7	10	11	15	10	7	2

Calculate arithmetic mean.

Answer 1

Heights (inches) (X)	No. of Persons (f)	Multiplication of the value of X and frequency (fX)
57 59 61 63 65 67 69 71 73	1 3 7 10 11 15 10 7 2	57 177 427 630 715 1005 690 497 146
	Σf = 66	Σfx = 4344

Arithmetic mean will be:
$$\begin{gathered} \overline{\mathit{X}}=\frac{\mathit{\Sigma }\mathit{f}\mathit{x}}{\mathit{\Sigma }\mathit{f}} \\ \mathrm{or},\overline{\mathit{X}}\mathit{=}\frac{4344}{66} \\ \mathit{\Rightarrow }\overline{X}=65.82 \end{gathered}$$

So, the average height is 65.82 inches.