Study the leverage effect with this tool. Leverage enable you to experiment with the leverage effect. You can create a random sample of data noisy points on a line. Dragging one of the points away from the regression line, immediately shows the effect, as the regression line is recalculated and moves according to the current data set.
Whne talking about "leverage" we most often refer to an undesirable effect which is experienced with regression analysis.
It basically means that a single data point which is located well outside the bulk of the data (an "outlier") has an overproportional effect on the resulting regression curve. Depending on the number of the samples and the distance of the outlier from the rest of the data, this effect may completely corrupt a regression model which would be quite good in the absence of an outlier.

The license of this software is Freeware, you can free download and free use this calculator software.