If ∑(xi-8)=9, ∑(xi-8)2=45, i=1,2, ldots . .18 then standard deviation of x1, x2 ldots . x18 is

Question

If ∑(xi-8)=9, ∑(xi-8)2=45, i=1,2, ldots . .18 then standard deviation of x1, x2 ldots . x18 is (A) (3/2) (B) (4/9) (C) (9/4) (D) (2/3)

Tardigrade Admin · Accepted Answer

V(x-8)=(45/18)-((9/18))2=(5/2)-(1/4) V(x-8)=(9/4) ⇒ √V(x-8)=(3/2)

Q. If $\sum (x_{i} - 8) = 9, \sum (x_{i} - 8)^{2} = 45, i = 1, 2, \dots ..18$ then standard deviation of $x_{1}, x_{2} \dots . x_{18}$ is