If `sum_(i=1)^n(x_i+1)^2=9n` and `sum_(i=1)^n(x_i-1)^2=5n`, then standard deviation of these 'n' observations `(x_1)` is: (1) `2sqrt(3)` (2) `sqrt(3)` (3) `sqrt(5)` (4) `3sqrt(2)`

If sum_(i=1)^(n)(x_(i)+1)^(2)=9n and sum_(i=1)^(n)(x_(i)-1)^(2)=5n, then standard deviation of these backslash 'n' observations (x_(1)) is: (1)2sqrt(3)(2)sqrt(3)(3)sqrt(5)(4)3sqrt(2)

If sum_(i=1)^n (x_i -a) =n and sum_(i=1)^n (x_i - a)^2 =na then the standard deviation of variate x_i

If sum_(i=1)^(5) (x_(i) - 6) = 5 and sum_(i=1)^(5)(x_(i)-6)^(2) = 25 , then the standard deviation of observations

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

If sum_(i=1)^(n)(x_(i)-2)=110, sum_(i=1)^(n)(x_(i)-5)=20 , then what is the mean?

If sum_(i=1)^(2n)cos^(-1)x_(i)=0 , then sum_(i=1)^(2n)x_(i) is :

lim_ (n rarr oo) sum_ (n = 1) ^ (n) (sqrt (n)) / (sqrt (r) (3sqrt (r) + 4sqrt (n)) ^ (2))

For all n in N,1+(1)/(sqrt(2))+(1)/(sqrt(3))+(1)/(sqrt(4))++(1)/(sqrt(n))