Mock Test Q4 Bi-Serial why is Population SD used ?

[Tejasvi Hegde]

In Mock test answer PDF its using Population Standard Deviation.

But as per teaching and in all formula Sample Sample Deviation is used. (Sx)

Even the question data mentioned  as Sample " In an organization, data from a sample of 10 employees is collected. "   

Why is Population SD is used in this ?

[Statistics 1 Support 1]

Hello,

You can use the sample standard deviation for calculating the point bi-serial coefficient, but in that case you need to use the sample correction in the formula. Instead of using sqrt(p0 *p1), use sqrt[(n0/n-1)(n1/n)].  But if you are using population standard deviation for calculation, then use sqrt(p0*p1).

In tutorial 4, there is a mistake, we will send an announcement.

Also, please find the screenshot attached here for the formula.

Thanks

Nikita

Statistics course support team

[Tejasvi Hegde]

Thank Nikita.

But that mistake in tutorial, (because learners follow what's in tutorial) would take out marks :(

Hope marks will be given if such situations happens in Qualifier exams ? 

[Pragati Mungekar]

Dear Support Team,

This is too early to make an announcement for the next 2021 Qualifier Exam to be held in April !!!!

--
You received this message because you are subscribed to the Google Groups "Discussion forum for Statistics for Data Science I" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ma1002-discus...@nptel.iitm.ac.in.
To view this discussion on the web visit https://groups.google.com/a/nptel.iitm.ac.in/d/msgid/ma1002-discuss/57d8fb2b-50bf-476e-b606-55881932f5c6n%40nptel.iitm.ac.in.