Solve this:
Q.30. The mean of the following frequency distribution is 47. Find the value of 'p'.
Classes 0-
20
20-
40
40-
60
60-
80
80-
100
Frequency 8 15 20 p 5

Dear student,

Given:- Mean x=47we know, x¯=fixifiNow, calculating fixi and fi
Class Frequency fi Class mark xi=lower limit+upper limit2 fixi
0-20 8 10 80
20-40 15 30 450
40-60 20 50 1000
60-80 p 70 70p
80-100 5 90 450
  fi=48+p   fixi=1980+70p

Mean x=fixifi47=1980+70p48+p4748+p=1980+70p2256+47p=1980+70p2256-1980=70p-47p276=23pp=27623p=12Thus the value of p is 12
Regards
 

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