Page 6 - LN

Here N = 100

Take a point A(0, 50) on y-axis and draw AP || x-axis meeting the curve at P.
Draw PM x axis, intersecting the axis at M.
Then, OM = 35 units
Hence, median = 35.
Notes:
(i)The Scale may not be the same on both axes
(ii)If we join the points by straight lines instead of free hand,we get a frequency polygon
(iii)For drawing an ogive, it should be ensured that the class intervals are continuous.If
class intervals are not continuous, then convert them into continuous form.

Example-2: An agriculture research officer measured the heights (to the nearest
centimetre) of 100 test plants after two months of growth. The distribution of
heights is shown below:
Heights 1 - 5 6 - 10 11 - 15 16 - 20 21 - 25 26 - 30
Number of plants 3 5 9 31 38 14

Construct more than ogive for the above data.
Solution:-

Here, the given data is in inclusive form. We, first, convert it into exclusive (continuous)
form.

6