Question 5 (a) A financial investment company administers an aptitude test to all new sales executives. Management is interested in the extent to which the test is able to predict their eventual success. A random sample of eight sales executives is taken, their average weekly sales (), in $'000) and aptitude test scores (x) are summarized below: [x=565, [y=1374, _ x2 =40799, _ y' =265108, _ xy=101087 (1) Find the "best fit' equation of average weekly sales on aptitude test score. (ii) Interpret the estimate of regression coefficients. Estimate the average weekly sales of a sales executive whose aptitude test score is 100. (b) A publishing company is developing a model for predicting textbook sales for books. It is considered that volumes sold (y, in 000) can be affected by number of pages (x, ), number of competing books (x,), advertising budget (x, , in $'000) and age of author (x,). A random sample of fifteen books in taken and a multiple linear regression is fitted with the outputs provided below: Coefficient Standard error Intercept -125.3078 31.0821 0.1759 0.0398 -1.5738 1.9959 1.5917 0.4445 X , 1.6137 0.6250 ANOVA table Source SS df MS Regression 30960.3270 Residual a Total 36648.4 14 Write down the 'best fit' equation. Calculate the missing values a to f in the ANOVA table