In an examination, 25 students obtained the following marks. Find out coefficient of range of the marks.

Marks 5−9 10−14 15−19 20−24 25−29 30−34 35−39

Number of Students 1 3 8 5 4 2 2

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Solution

Converting the inclusive series into exclusive series,

Marks No. of Students

4.5 − 9.5
9.5 − 14.5
14.5 −19.5
19.5 −24.5
24.5 −29.5
29.5 −34.5
34.5 −39.5 1
3
8
5
4
2
2

Here,
Highest Marks value (H)=39.5
Lowest Marks value (L)=4.5

$Coefficient of Range (C R) = \frac{H - L}{H + L} or, CR = \frac{39.5 - 4.5}{39.5 + 4.5} or, CR = \frac{35}{44} \Rightarrow CR = 0.79$

Hence, the Coefficient of range of marks in the above series is 0.79

Suggest Corrections

Marks	10−20	20−30	30−40	40−50	50−60	60−70	70−80	80−90	90−100
Number of Students	4	10	16	22	20	18	8	2	5

Marks	0−9	10−19	20−29	30−39	40−49	50−59
No. of Students	3	7	15	25	10	4

Marks (more than)	0-9	10-19	20-29	30-39	40-49	50-59
No of students	2	5	15	25	10	3

Marks	5−9	10−14	15−19	20−24	25−29	30−34	35−39
Number of Students	1	3	8	5	4	2	2

Marks	No. of Students
4.5 − 9.5 9.5 − 14.5 14.5 −19.5 19.5 −24.5 24.5 −29.5 29.5 −34.5 34.5 −39.5	1 3 8 5 4 2 2