From the following data calculate range and coefficient of range:

Marks 10 20 30 40 50 60 70

No. of Studends 8 12 7 30 10 5 2

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Solution

Marks No. of Students

10 8

20 12

30 7

40 30

50 10

60 5

70 2

Highest value (H) = 70
Lowest value (L) = 10

Range = Highest value − Lowest value

i.e. R = H−L

or, R = 70 − 10= 60 marks

$Coefficient of Range = \frac{H - L}{H + L} = \frac{70 - 10}{70 + 10} = \frac{60}{80} = 0.75$

Note- As the given data series is a discrete series, where in order to calculate Range, frequencies are not taken into account. Hence, in this case, the formula for Range remains the same as it is for the individual series.

Suggest Corrections

Marks	10−20	20−30	30−40	40−50	50−60
No. of students	12	18	14	63	19

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

Marks	0−10	10−20	20−30	30−40	40−50	50−60	60−70	70−80
No. of persons	5	10	20	40	30	20	10	4