Question

The following table gives the height of trees:
 

Height	No. of trees
Less than 7 Less than 14 Less than 21 Less than 28 Less than 35 Less than 42 Less than 49 Less than 56	26 57 92 134 216 287 341 360

Draw 'less than' ogive and 'more than' ogive.

 

Answer 1

Consider the following table.
 

Height (less than)	Height-class	No. of trees	Cumulative frequency	Suitable points
7	0-7	26	26	(7, 26)
14	7-14	31	57	(14, 57)
21	14-21	35	92	(21, 92)
28	21-28	42	134	(28, 134)
35	28-35	82	216	(35, 216)
42	35-42	71	287	(42, 287)
49	42-49	54	341	(49, 341)
56	49-56	19	360	(56, 360)

Now, draw the less than ogive using suitable points.

Now, prepare the cumulative frequency table for more than series.

Height	No. of trees	Height (more than)	Cumulative frequency	Suitable points
0-7	26	0	360	(0, 360)
7-14	31	7	334	(7, 334)
14-21	35	14	303	(14, 303)
21-28	42	21	268	(21, 268)
28-35	82	28	226	(28, 226)
35-42	71	35	144	(35, 144)
42-49	54	42	73	(42, 73)
49-56	19	49	54	(49, 54)

Now, draw the more than ogive using suitable points.