Consider the following data for a company's monthly advertising expenditure and their sales. (a) Produce a scatter plot for these data, and comment on the relationship between advertising and sales. (b) Calculate the sample correlation coefficient. Does this agree with what you can see in your plot in part (a)? (c) Perform a linear regression analysis on these data, and obtain the linear re- gression equation. (d) Plot the regression line on your scatter diagram in part (a). (e) If the company were to spend f112, 000 on advertising in a month, what could we expect their sales to be? Month Advertising (2000's) Sales (f Millions) January 100 11.2 February 90 12.1 March 110 13.2 April 120 15.1 May 115 14.2 June 95 10.2 July 105 12.5 August 130 16.6 September 118 14.8 October 100 10.8 November 115 11.2 December 128 15.9