# Help with finding the variance of an unbiased estimator

#### janebondarenko

##### New Member
I need to find the variance of this estimator for population mean, I have already proven that it is unbiased, but I cannot fully calculate its variance. Could anyone please help?

#### Dason

Do you know the variance of each of the individual components

#### janebondarenko

##### New Member
Do you know the variance of each of the individual components
No, it’s not given, I have to express through the constants and sample means.

#### Dason

I'm asking do you know how to express the variance of something like $$\bar{X}_1$$

#### janebondarenko

##### New Member
In terms of mu, here is the task itself

#### Dason

I'm asking do you know how to express the variance of something like $$\bar{X}_1$$
I'm asking do you know how to express the variance of something like $$\bar{X}_1$$
I'm asking do you know how to express the variance of something like $$\bar{X}_1$$