question_answer

If \[{{f}_{1}}\] is the frequency of the variable xi and \[\overline{x}\] is the arithmetic mean, then always

A)  \[\sum\limits_{i=1}^{{}}{{{f}_{i}}({{x}_{i}}+\overline{x})=0}\]

B)         \[\sum\limits_{i=1}^{{}}{{{f}_{i}}({{x}_{i}}-\overline{x})=0}\]  

C) \[\sum\limits_{i=1}^{n}{{{f}_{i}}{{({{x}_{i}}+\overline{x})}^{2}}=0}\]

D)         \[\sum\limits_{i=1}^{n}{{{f}_{i}}{{({{x}_{i}}-\overline{x})}^{2}}=0}\]