Let `barx` be the mean of `x_(1), x_(2), ………, x_(n)` and `bary` be the mean of `y_(1), y_(2),……….,y_(n)`. If `barz` is the mean of `x_(1), x_(2), ……………..x_(n), y_(1), y_(2), …………,y_(n)`, then `barz` is equal to

Options

A. ` (overlinex +overliney)`
B. `1/2(overlinex + overliney)`
C. `1/n (overlinex+overliney)`
D. `1/(2n)(overlinex +overliney)`

Answer

b

Explanation

` overlinez= (((x_(1) +x_(2) +….+x_(n)) + (y_(1) +y_(2) +…..+y_(n))))/(2n)`
But , `overlinex = (x_(1)+x_(2)+….+x_(n))/n Rightarrow (x_(1)+x_(2) +…..+ x_(n)) = noverlinex`
`overliney=(y_(1)+y_(2)+....+y_(n))/nRightarrow(y_(1)+y_(2)+......+y_(n))noverliney`
`overlinez=(noverlinex+noverliney)/(2n)=(n(overlinex+overliney))/(2n)=((overlinex+overliney))/2`