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If sum(i=1)^(9)(x(i)-5)=9andsum(i=1)^(9)...

If `sum_(i=1)^(9)(x_(i)-5)=9andsum_(i=1)^(9)(x_(i)-5)^(2)=45`, then the standard deviation of the 9 items `x_(1),x_(2),......,x_(9)` is

A

9

B

4

C

3

D

2

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