If the data points all line up on the line of best fit, what does this say about the data?
To think about this, let’s imagine some variables 𝑥 and 𝑦 and a positive line of best fit. According to this question, all of the data points fall on the line somewhere. But because we haven’t been told anything further, we should remember that it’s also possible that a line of best fit has a negative slope and could look like this. If all the data points fall on a line like this, what does it say about the data?
For either of these cases, we can make the same statement. We can say that there is very strong correlation between the variables. The more data points that fall on our line of best fit, the stronger the correlation we say between the two variables are.