where n is the sample size; x is a data value for the explanatory variable; is the mean of the x-values; is the standard deviation of the x-values; similarly, for the terms involving y. Use the simula...where n is the sample size; x is a data value for the explanatory variable; is the mean of the x-values; is the standard deviation of the x-values; similarly, for the terms involving y. Use the simulation below to investigate how the value of relates to the direction and strength of the relationship between the two variables in the scatterplot. In the simulation, use the slider bar at the top of the simulation to change the value of the correlation coefficient (r) between −1 and 1.