CT3- CH 10 Point Estimation

Hi Team,

In Ch 10 questions 10.2 & 10.3 while calculating 2nd order moments, Two different methods are used for Variance. First is 1/n and second is 1/n-1.
Which method should we utilize while obtaining estimate as per exam prospective in such questions?

Are both methods correct?
Please suggest

 

we can use either, both are correct. However the answers will be different.