STATS 2 PARTIAL CORRELATION

Question 1

What could be the reasons for correlation between two variables?

Answer 1

One variable could cause change in another
Both variables could cause change in one another
A third variable may be causing the changes in the two variables

Question 2

What is it called when a third variable is causing the changes in two variables of interest?

Answer 2

A spurious correlation

Question 3

What does it mean “to control” for a variable C when computing correlation between X and Y?

Answer 3

Looking at the correlation between X and Y after removing effects of C from both X and Y

Question 4

What is a zero-order correlation?

Answer 4

The correlation between X and Y, ignoring the existence of confounds

Question 5

What is a partial correlation?

Answer 5

The correlation between X and Y, controlling for C, by removing the variance in X and Y shared with C

Question 6

What are the degrees of freedom when testing the significance of partial correlation?

Answer 6

N-3 (because 3 variables involved)