Q30 of 39 Page 1

If the median of the following frequency distribution is 32.5. Find the values of f1 and f2.

Or


The marks obtained by 100 students of a class in an examination are given below.



Draw ‘a less than’ type cumulative frequency curves (orgive). Hence find median.


Sum of frequency = 40


f1 + 5 + 9 + 12 + f2 + 3 + 2 = 40


f1 + f2 = 9


l = lower limit of median class (30 – 40) = 30


n = number of observations = 31 + f1 + f2


cf = cumulative frequency of class preceding to the median


class = 14 + f1


f = frequency of the median class = 12


h = class size = 10




2.5 × 1.2 = 20 – 14 - f1


f1 = 3


f2 = 9 – 3


f2  = 6


OR



n = number of observations = 100


n/2 = 50


CF of median class = 56


l = lower limit of median class (25 – 30) = 25


cf = cumulative frequency of class preceding the median class = 31


f = frequency of the median class = 25


h = class size = 5



Median = 28.8


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