Researchers have good reason to believe that the weight X of a particular type of animal perfectly predict its length Y by the formula Y = a + bX. However, the data collected by the researchers has been disturbed by errors in measurements of the lengths Y. They are left with the following table. Weight X 2 6 8 10 Length Y 3 5 8 From the table, we can calculate: EX =30 EY =27 EXY =184 E X2 =220 (EX)' =900 N = 5 Use the regression formula to calculate the researcher's best guess for b. O .38 O .79 O .31 O .55