Ogive (cumulative frequency curve) Example-2

2. Draw Ogive (cumulative frequency curve)
Class Frequency
10 - 20 15
20 - 30 25
30 - 40 20
40 - 50 12
50 - 60 8
60 - 70 5
70 - 80 3

Solution:
To draw Less than type cumulative frequency curve, we first prepare the following table

Class	Frequency `f`	< Upper	`cf`
0 - 10	-	10	0
10 - 20	15	20	0 + 15 = 15
20 - 30	25	30	15 + 25 = 40
30 - 40	20	40	40 + 20 = 60
40 - 50	12	50	60 + 12 = 72
50 - 60	8	60	72 + 8 = 80
60 - 70	5	70	80 + 5 = 85
70 - 80	3	80	85 + 3 = 88

To draw More than type cumulative frequency curve, we first prepare the following table

Total frequency = 88

Class	Frequency `f`	> Lower	`cf`
10 - 20	15	10	88
20 - 30	25	20	88 - 15 = 73
30 - 40	20	30	73 - 25 = 48
40 - 50	12	40	48 - 20 = 28
50 - 60	8	50	28 - 12 = 16
60 - 70	5	60	16 - 8 = 8
70 - 80	3	70	8 - 5 = 3
80 - 90	-	80	3 - 3 = 0

This material is intended as a summary. Use your textbook for detail explanation.
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2. Example-2