Question

Mean and variance

If an estimator is unbiased, then its value is always the value of the parameter, its expected value is always the value of the parameter, O it variance is the same as the variance of the parameter.

Answer can be one or multiple

Answer 1

Option 2nd is the right option

For example let x follow normal(u,sig^2)

And xbar = (x1+x2....+xn)/n is a estimator which is unbiased

So first option is not correct Because sample mean can not always be equals to parameters because it is based on random observation

Now 2nd option is correct

Because E(xbar) = u this imply xbar is unbiased ,again

Var(xbar) = sig^2/n which is not equal to variance and also we can't calculate variance of a parameter

So only option 2 is right option