Question

if the mean of first give observation is x,x+2,x+4,x+6,x+8 is 11 then find the mean of first three observations

Answer 1

Given:

(x+x+2+x+4+x+6+x+8)/5=11

Mean is the addition of all terms divided by the number of terms.

So,

5x+20=55

=5x=35

=x=35/5=7

Now mean of first three observations=(x+x+2+x+4)/3

=(3x+6)/3

=(21+6)/3

=27/3=9

9 is the mean of first 3 observations.

Hope it helps.