Question

Weight of 60 eggs were recorded as given below:
$\begin{array}{cccccccc}\text{Weight (in grams)}& 75-79& 80-84& 85-89& 90-94& 95-99& 100-104& 105-109\\ \text{Number of eggs}& 4& 9& 13& 17& 12& 3& 2\end{array}$
Calculate their mean weight to the nearest gram.

Answer 1

Weight (in grams)	Number of eggs (fi)	Class mark (xi)	di= xi-92	ui = (xi−92)/5	fiui
74.5 - 79.5	4	77	-15	-3	-12
79.5 - 84.5	9	82	-10	-2	-18
84.5 - 89.5	13	87	-5	-1	-13
89.5 - 94.5	17	92	0	0	0
94.5 - 99.5	12	97	5	1	12
99.5 - 104.5	3	102	10	2	6
104.5 - 109.5	2	107	15	3	6
Total	∑fi=60				∑(fi×ui)=−19

The mean of given data is given by

$\overline{x}$=a+(∑fiui/∑fi)×h

= 92 + (−19/60) x 5

= 92 - 1.58

= 90.42

≈≈ 90

Thus, the mean weight to the nearest gram is 90g