Question

The following table shows prices per 100g of tea of different brands. Using quantities as weight, find out weighted arithmetic mean of the prices.

Prices per 100g in ₹	2.50	3	3.50	4	4.25	5
Quantity	10	8	8	4	4	2

Answer 1

Price (X)	Quantity (W)	WX
2.50 3 3.50 4 4.25 5	10 8 8 4 4 2	25 24 28 16 17 10
	∑W = 36	∑WX=120

Calculating the weighted arithmetic mean of the prices:

$$\begin{gathered} {\overline{\mathit{X}}}_{\mathit{W}}=\frac{\mathit{\Sigma }\mathit{W}\mathit{X}}{\mathit{\Sigma }\mathit{W}} \\ \mathrm{or},{\overline{X}}_w=\frac{120}{36} \\ \Rightarrow {\overline{X}}_w=3.33 \end{gathered}$$

Hence, the weighted arithmetic mean of the prices is 3.33.