Professor Katula feels that there is a relation between the number of hours a statistics student studies each week and the student's age. She conducts a survey in which 26 statistics students are asked their age and the number of hours they study statistics each week. She obtains the following results:

(a) Draw a scatter diagram of the data. Comment on any potential influential observations.
(b) Find the least-squares regression line using all the data points.
(c) Find the least-squares regression line with the data point (35, 8.1) removed.
(d) Draw each least-squares regression line on the scatter diagram obtained in part (a).
(e) Comment on the influence that the point (35, 8.1) has on the regression line.

Age, Hours Studying, y x Age, Hours Studying, y x Age, Hours Studying, y 18 4.2 19 5.1 22 2.1 18 1.1 19 2.3 22 3.6 18 4.6 1.7 24 5.4 18 3.1 20 6.1 25 4.8 18 5.3 20 3.2 25 3.9 18 3.2 20 5.3 26 5.2 19 2.8 21 2.5 26 4.2 19 2.3 21 6.4 35 8.1 3.2 19 21 4.2