Calculate the value of mode from the following data by using the formula. Mode = 3 median - 2 mean:

marks 10 20 30 40 50 60 70 80 90

(less than)

no. of students 5 15 98 242 367 405 425 438 439.

 
Class interval Frequency
Fi
Mid value
Xi
 
Cumulative frequency

FiXi

0-10 5 5 5 25
10-20 10 15 15 150
20-30 83 25 98 2075
30-40 144 35 242 5040
40-50 125 45 367 5625
50-60 38 55 405 2090
60-70 20 65 425 1300
70-80 13 75 438 975
80-90 1 85 439 85
  fi=439     fi xi=17365


Mean=fixifi
=17365439=39.56
Median class is 40-50 as n/2 is 219.5

Median=Li   +N2-cff×i=40+4392-242144×10=40-1.5638.43
Mode=3Median-2 Mean
=3*38.43-2*39.56
=115.29-79.12
=36.17
 

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