I should run a test to determine whether variable A affect variable B or viceversa.
What type of test should I use?
Imagine that we measure the time slept per night (A) and the activity performed during a day (B) in several subjects. In particular we have a median of 4 nights and 4 days measured for each subject.
How would you approach the problem?
1) estimate how much the night (A) is correlated with the following day (B) 2) estimate how much the day (B) is correlated with the following night (A+1) 3) take the highest correlated condition
Is there a test that takes into account this situation? Thanks