One way to understand the strength of the correlationcoefficient is to take the absolute value and then see how close itis to 1. The reason that makes it easier for some people tounderstand is that they get confused by the negative sign. Thecloser it is to -1 or +1, the stronger the correlation, as itdoesn't consider the direction of the correlation. However, manystudents get confused by the negative aspect and assume that apositive correlation coefficient is stronger. Therefore, if yourefer to the absolute value, that will eliminate any confusionregarding the negative or positive sign. On the topic of arepresentative sample, it's debatable how many data points youactually need. At what point do you think it's necessary to look atevery data point, compared to a representative sample? When wouldyou feel comfortable that your sample truly represents thepopulation?
