We observe that the number of packets less than 200 is 0. Similarly, less than 201 include the number of packets from 0-200 as well as the number of packets from 200-201.
So, the total number of packets less than 201 is 0+13=13. We say that, the cumulative frequency of the class 200-201 is 13. Similarly, for other class. Weight(in~g) & Number of packetsLess than 2000Less than 2010+13=13Less than 20227+13=40Less than 20318+40=58Less than 20410+58=68Less than 2051+68=69Less than 2061+69=70
To draw the less than type ogive, we plot the points (200, 0), (201, 13), (202, 40), (203, 58), (204, 68), (205, 69) and (206, 70) on the paper and join by free hand. ∵
Total number of packets(n) =70
Firstly, we plot a point (0,35) on Y-axis and draw a line y=35 parallel to X-axis. The line cuts the less than ogive curve at a point. We draw a line on that point which is perpendicular to X-axis. The foot of the line perpendicular to X-axis is the required median. ∴