Question

 Compute the mean for following data:

Class	1-3	3-5	5-7	7-9
Frequency	12	22	27	19

Answer 1

The given data is shown as follows:

Class	Frequency	Class mark `(X_i)`	`f_i X_i`
1-3	12	2	24
3-5	22	4	88
5-7	27	6	162
7-9	19	8	152
Total	∑ `f_i = 80`		∑`f_i X_i = 426`

The mean of given data is given by

x  = `( sum_(i) f_i x_i)/(sum_i f_i)`

    =`426/80`

   =5.325

Thus, the mean of the following data is 5.325.