In: Statistics and Probability
5. Give an example of a scatterplot for which |r| is very small, but for which there is a very strong relationship between the explanatory and response variables.
6. What are three reasons |r|~ 0?
5. Let us consider the following scatter plot.
The correlation coefficient r of the two variables = cor (x,y)=-0.01535841
So, |r|=0.01535841 is very small but the parabolic structure of the scatter plot reveals that the relationship between x and y is,
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6. The non linear relationship deviates a lot from linearity. Since correlation is a measure of linear relationship of x and y, we fond |r| is almost close to 0.