Applet Exercise Access the applet Removing Points from Regression. Sometimes removing a point from those used to fit a regression model produces a fitted model substantially different that the one obtained using all of the data (such a point is called a high-influence point).
a. The top graph gives a data set and fitted regression line useful for predicting a student's weight given his or her height. Click on any data points to remove them and refit the regression model. Can you find a high influence data point in this data set?
b. Scroll down to the second graph that relates quantitative SAT score to high school rank. Does the slope of the fitted regression line surprise you? Can you find a high-influence data point? Does removing that data point produce a regression line that better meets your expectation regarding the relationship between quantitative SAT scores and class rank?
c. Scroll down to the remainder of the data sets and explore what happens when different data points are removed.