Formula: 2 Marks
Table: 2 Marks
Graph: 2 Marks
To draw the 'less than ogive', first we prepare the cumulative frequency table as given below:
ObservationsFrequencyObservationsCumulative frequency(in classes)(in ′less than′ form)0−104Less than 10410−209Less than 201320−3015Less than 302830−4014Less than 404240−508Less than 5050 Now, we mark the upper class limits along the x-axis on a suitable scale and the corresponding cumulative frequencies along the y-axis on a suitable scale. We plot the points (0, 0), (10, 4), (20, 13), (30, 28), (40, 42) and (50, 50). We join the plotted points by a freehand curve to obtain the required ogive as shown below.
Total no. of observations = n = 50.
To find the median from this ogive, first we locate the number
n2=502=25 on the y-axis.
![](https://search-static.byjusweb.com/question-images/byjus/infinitestudent-images/ckeditor_assets/pictures/70888/content_1.jpg)
From the point marked 25 on they-axis, we draw a horizontal line parallel to the x-axis intersecting the ogive at point A. From the point A, we draw a vertical line perpendicular to the x-axis meeting it at B. The value of point B on x-axis is 28. Hence, the required median is 28.