1. In order to increase sales, a car dealership has developed a 30-second TV ad to advertise a discount event. The data on the number of ads per day and number of cars sold are provided in the following table: No. of ads per day, x 1 1 2 2 2 3 3 3 4 4 4 No. of cars sold, y 21 18 17 24 22 26 34 29 32 45 41 35 [x, = 30 , Ey, = 344, Ex, = 90 , Ey? = 10 742 , Ex,y, = 969 (a) Plot a scatter diagram (using SAS, see class example part (i)) to get an idea of the form of the relationship between the No. of ads per day and the No. of cars sold. Does the scatter diagram indicate an approximately straight line? (b) State a SLR model, making sure you give all assumptions necessary for statistical inference. (c) Find the least squares estimates of , and B, . Find the least squares fitted regression line. For the rest of the question assume that the assumptions hold. (d) Find s2, an estimate of 62. (e) Use the t-test to test whether there is a significant linear relationship between the No. of ads per day and the No. of cars sold. Use a = 0.05. (f) Find a 95% confidence interval for B, . (g) Set up the ANOVA table and hence test whether there is a significant linear relationship between the No. of ads per day and the No. of cars sold. Use a = 0.05