Question

larry has noticed that when he carries around his lucky rock, his students seem to be nicer to him. can one conclude that this positive correlation shows a causal relationship?
a. yes, because larry decides whether or not to put his lucky rock in his pocket before he encounters people during the day
b. yes, because it is not a negative correlation.
c. no, because lucky rocks only work for children.
d. no, because it is possible that people are nice to larry because of a
other factor that also causes him to put the rock in his pocket.

Explanation:

Correlation does not imply causation. Just because there is a positive correlation between Larry carrying the lucky rock and students being nicer to him does not mean the rock causes the niceness. There could be a confounding variable (a "lurking" or "other" factor) at play. For example, maybe on days Larry is in a good mood (unrelated to the rock), he carries the rock and also interacts more positively with students, who then respond in kind.

Answer:

D. No, because it is possible that people are nice to Larry because of a\( \textcolor{red}{\text{other factor}} \) that also causes him to put the rock in his pocket.