STATISTICS A6

In Kiswahili test the following marks were recorded.

marks	10-19	20-29	30-39	40-49	50-59	60-69
No. of students	2	4	9	7	5	3

Calculate the mean.

Solution

Here you are required to produce the frequency distribution table.

Class interval	Class mark (x)	Frequency(f)	fx
10-19	14.5	2	29
20-29	24.5	4	98
30-39	34.5	9	310.5
40-49	44.5	7	311.5
50-59	54.5	5	272.5
60-69	64.5	3	193.5
		∑f = 30	∑fx = 1215

Mean = ∑fx

               ∑f

Mean = 1215

                 30

Mean =  40.5

         

Hence Mean =  40.5