##### Part 1

What does it mean to say “correlation does not imply causation”?

The fact that two variables are strongly correlated implies a cause-and-effect relationship between the variables.

Two variables that have a cause-and-effect relationship are never correlated.

The fact that two variables are strongly correlated does not in itself imply a cause-and-effect relationship between the variables.

Your answer is correct.

Two variables can only be strongly correlated if there existed a cause-and-effect relationship between the variables.

##### Part 2

Which of the following pairs of variables have correlation, but no cause-and-effect relationship?

Number of school buses at a school and the number of students at a school

The number of students per teacher at a school and the number of teachers at a school

Number of school buses at a school and the number of teachers at a school

Your answer is correct.

The number of students per teacher at a school and the number of students at a school