Question

please help me fast
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Answer 1

Answer:

This is actually quite simple

first mean method

fi     xi         fixi

6    2.5     15

12   6.5     78

26  12.5    325

20  21.5    430

fixi=848

fi=64

848/64

13.25

second mean method

di=xi-a

lets take a= 12.5

di    fidi

-10  -60

-6    -72

0     0

9     180

fidi=48

a + fidi/fi

12.5 + 48/64

12.5+0.75

13.25

third mean method

ui=di/h

h=3

ui             fiui

-10/3       -20

-2          -24

0          0

3         60

fiui=16

a+fiui/fi*h

12.5 + (16/64)*3

12.5+48/64

12.5+0.75=13.25

hence proved

Answer 2

on solving the problem by any three methods of mean

the answer will be 13.25