STATISTICS 1

In Kiswahili test the following marks were recorded.

marks	10-19	20-29	30-39	40-49	50-59	60-69
No. of students	3	8	10	8	7	4

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	3	43.5
20-29	24.5	8	196
30-39	34.5	10	345
40-49	44.5	8	356
50-59	54.5	7	381.5
60-69	64.5	4	258
		∑f = 40	∑fx = 1580

Mean = ∑fx

               ∑f

Mean = 1580

                 40

Mean =  39.5

         

Hence Mean =  39.5

TRY THIS...................

In a French test the following marks were recorded.

marks	10-14	15-19	20-24	25-29	30-34	35-39
No. of students	4	7	12	8	5	4

Calculate the mean.