Question

A milk centre sold milk to 50 customers. The table below gives the number of customers and the milk they purchased. Find the mean of the milk sold by direct method.
Milk Sold (Litre) : No. of Customers
1-2 : 17
2-3 : 13
3-4 : 10
4-5 : 7
5-6 : 3

Answer 1

Step-by-step explanation:

$\begin{tabular}{|l|l|l|l}</p><p>\cline{1-4}</p><p>Class interval & Frequency(f_i) & Class mark(x_i) & \multicolumn{1}{l|}{x_if_i} \\ \cline{1-4}</p><p>1-2 & 17 & 1.5 & \multicolumn{1}{l|}{25.5} \\ \cline{1-4}</p><p>2-3 & 13 & 2.5 & 32.5 \\ \cline{1-4}</p><p>3-4 & 10 & 3.5 & \multicolumn{1}{l|}{35} \\ \cline{1-4}</p><p>4-5 & 7 & 4.5 & \multicolumn{1}{l|}{31.5} \\ \cline{1-4}</p><p>5-6 & 3 & 5.5 & \multicolumn{1}{l|}{16.5} \\ \cline{1-4}</p><p>Total & 50 & & \multicolumn{1}{l|}{141} \\ \cline{1-4}</p><p>\end{tabular}$

$Mean = \frac{\Sigma \: x_if_i}{\Sigma \: f_i} \\ \\ = \frac{25.5 + 32.5 + 35 + 31.5 + 16.5}{50} \\ \\Mean = 2.82$

Mean of the given observation is 2.82 litres

Hope it helps you