A frequency polygon is the polygon obtained
by joining the midpoints of upper horizontal sides of all the rectangles in the
histogram. Frequency polygons can also be drawn independently without drawing
histogram.
For
this we first find class mark of a class interval by using the formula
Class mark=(
upper limit + lower limit) /2
Here, the given frequency distribution is
not continuous as it is in inclusive form(0-10, 11-20).
To Convert the intervals in continuous form
firstly we find the difference between
upper limit of a class and the lower limit of its succeeding class then add and
subtract half of this difference to upper limit and lower limit..
For continuous distribution we get first
interval as
(1-0.5) – (6+0.5)= 0.5 -6.5.
Class mark of first interval= (0.5+6.5)/2=
7.0/2= 3.5
First we make the class intervals
continuous & find the class marks of all the class intervals & the
modified table of given data is in the attachment.
Now frequency polygon for both teams are in
the attachment.
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Hope this will help you.....