can help to identify relationships between variables,
and graphs can show these relationships visually.
A positive correlation exists when one variable increases, so does the other.
In this case one variable is access to textbooks and the other is exam scores.
However, correlation may not imply causation, especially if there are inherent
biases in the samples.
- What are some possible sample biases in this hypothetical study?
- sample size too small
- income levels