Question

The following table shows the distribution of the heights of a group of factory workers:

Ht. (cm):	150-155	155-160	160-165	165-170	170-175	175-180	180-185
No. of workers:	6	12	18	20	13	8	6

1. Determine the cumulative frequencies.
2. Draw the ‘less than’ cumulative frequency curve on graph paper. Use 2 cm = 5 cm height on one axis and 2 cm = 10 workers on the other.

Answer 1

Height (in cm)	No. of workers	c.f.
150-155	6	6
155-160	12	18
160-165	18	36
165-170	20	56
170-175	13	69
175-180	8	77
180-185	6	83

We plot the points (155, 6), (160, 18), (165, 36), (170, 56), (175, 69), (180, 77), and (185, 83) on the graph and join them in freehand to obtain an ogive.