The table below shows the amount a company spent (in units of 100,000 rupees) on marketing its product from January to August 2010 and the resulting sales (in units of million rupees). Amount Spent on 12.2 8.4 14.1 15.2 15.8 16.4 17.2 18.2 marketing the product, x Sales, y 2.4 3.0 3.8 4.9 6.2 7.5 7.4 8.5 (a) Draw a scatter diagram to illustrate the data given in the table. Comment on the plot. [5 marks] (b) Calculate the correlation coefficient, r, between x and y. Calculate r2. Interpret the value of r and of r2. [10 marks] (c) The equation of the regression line of yon x can be written as y = a + bx. Draw this line on the scatter diagram. Interpret the value of a and of b. [12 marks] (d) Forecast the sales for the month of September 2010 if the company spent Rs1920000 on marketing during that month. Comment on the reliability of this estimate. [3 marks]