Question:
If $\bar{x}$ is the mean of $x_{1}, x_{2}, x_{3}, \ldots, x_{n}$, then $\sum_{i=1}^{n}\left(x_{i}-\bar{x}\right)=?$
(a) $-1$
(b) 0
(c) 1
(d) n − 1
Solution:
(b) 0
If $\bar{x}$ is the mean of $x_{1}, x_{2}, x_{3}, x_{4, \ldots} x_{n}$, then we have:
$\sum_{i=1}^{n} x_{i}=\bar{x}$
$\mathrm{O} r$
$\sum_{\mathrm{i}=1}^{\mathrm{n}} \mathrm{x}_{\mathrm{i}}-\overline{\mathrm{x}}=0$