Expert/teacher guidance needed

[yugesh maitreyan]

Respected sir/madam,

for the point biserial correlation problems,

tutorial 4 - sample standard deviation was used,

mock test q4 - population standard deviation was used.

which standard deviation should be used in the problems?

please answer clearly.

Thanking you,

Yugesh Maitreyan

GCT Coimbatore

[Tejasvi Hegde]

Even I have query.

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

[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