Compute the mean marks obtained by the students from the following data:

Marks 0−4 4−8 8−12 12−16 16−20 20−24

No. of Students 7 9 16 8 6 4

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Solution

Class Interval
(Marks)
Mid-Values
(m) Students
(f) fm

0 − 4
4 − 8
8 − 12
12 − 16
16 − 20
20 − 24 2
6
10
14
18
22 7
9
16
8
6
4 14
54
160
112
108
88

$Σ f$ =50 $Σ f m$ =586

Calculating the mean marks using direct method:

$X = \frac{Σ f m}{Σ f} or, X = \frac{536}{50} \Rightarrow X = 10.72 marks$

Hence, mean marks obtained by the students are 10.72

Suggest Corrections

Marks	10−20	20−30	30−40	40−50	50−60	60−70
No. of Students	8	11	9	25	12	16

Marks	0-19	20-39	40-59	60-79	80-99
No. of students	4	8	32	16	8

Marks	5−15	15−25	25−35	35−45	45−55	55−65
No. of Students	8	12	6	14	7	3

Marks	0−4	4−8	8−12	12−16	16−20	20−24
No. of Students	7	9	16	8	6	4