A web platform (http://www.animation.statgrafia.pl/correlation) accompanying a previous paper (Teach Stat 31 (2009), 52–54) is described. The platform contains animations of a small simulation study based on the population presented in the above-mentioned paper, results of a similar but large simulation study based on the same population, and results of similar simulation studies based on seven 1000-element populations with various population correlation coefficients. With the platform, a teacher can explain how sample size influences bias and precision of the regular estimator of Pearson's correlation coefficient, and what in general the distribution of the correlation coefficient looks like.
