How do we find the unbiased estimate of the variance in this question?

[Chimchim]

I am struggling to prove b)ii). Please help! Thank you!

 

[Deleted member 4993]

I am struggling to prove b)ii). Please help! Thank you!

View attachment 10224

What does E(U) mean in this context?

What is the definition and mathematical expression for "unbiased" estimate of the variance?

 

[Chimchim]

What does E(U) mean in this context?

What is the definition and mathematical expression for "unbiased" estimate of the variance?

E(U) is the unbiased mean and I think the unbiased estimate of something is E(a)=a ?

 

[Chimchim]

What does E(U) mean in this context?

What is the definition and mathematical expression for "unbiased" estimate of the variance?

Please help!