CT3 sept 2016

Please anyone clarify qus. 13 part (v)
Is it the right way to calculate this:
Here, we need to find the value of X for which the CI for mean daily revenue is shortest. So it will be shortest if variance is shortest. By looking at the formula of variance, it seems that it will be shortest if X= X bar.
Please clarify asap... and rectify if I am wrong .
Thanks

 

Plz rply asap..

 

Yes, X= X bar will give the shortest CI. There was a similar question in last session's paper.

 

yaa, okay
Thankyou