Lecture 18 Flashcards
1
Q
What does correlation study rely on?
A
Relies on associations between variables that already exist
2
Q
How many variables will correlation include?
A
Only 2
3
Q
What does the Pearson r numerator represent?
A
Variation in scores associated with apparent linear relationship
4
Q
What does the Pearson r demoninator represent?
A
Variation associated with apparent linear relationship + variation in scores associated with everyone else
5
Q
What is range restriction?
A
How much room each variable has to vary
6
Q
If the range is restricted what effect can this have?
A
It can produce an artificially LOW correlation coefficient
7
Q
What are the negatives of correlation study?
A
- Difficult to confirm actual direction of possible cause/effect
- Impossible to know from data whether relationship is direct or indirect effect
