Q&A bank Q 3.26 (iii) (b)

The question asks if the estimator is consistent.

I know that if as n tends to inf mse becomes 0 then the estimator is consistent.

But how did they calculate MSE(est. sigma^2) to be (2/n)*(sigma^4)?????

 

Sorry to bump this thread, but can anyone help me with this?

Thanks!

 

Apply L'Hôpital's rule to the form of MSE derived in part (iii) a.

This will give the limit in a simplified form.

 

Thanks bapan!!!

Got it and worked.