devarshi-dt-logo

Question:

During the medical check-up of 35 students of a class, their weights were recorded as follows: Weight (in kg) Number of students Less than 38 0 Less than 40 3 Less than 42 5 Less than 44 9 Less than 46 14 Less than 48 28 Less than 50 32 Less than 52 35 Draw a less than type ogive for the given data. Hence obtain the median weight from the graph and verify the result by using the formula.

Solution:

Let us now plot the points corresponding to the ordered pairs given by (38,0),(40,3),(42,5),(44,9),(46,14),(48,28),(50,32) and (52,35) on a graph paper and join them by a free hand smooth curve.

Now,
Weight (in kg) Number of students (Frequency)
0-38 0
38-40 3
40-42 2
42-44 4
44-46 5
46-48 14
48-50 4
50-52 3

Mode: The class which have highest frequency. In this case, class interval 46-48 is the modal class.

Now, Lower limit of modal class, l=46, h=2, f1=14, f0=5, f2=4

We know that,
Mode = l + ((f1-f0)/(2f1-f0-f2)) * h
= 46 + ((14-5)/(2(14)-5-4)) * 2
= 46 + (9/19) * 2
= 46 + 0.95
Mode = 46.95, verified.