he linear regression equation and the value of the linear correlation coefficient r. Round to 2 decimal 19) The paired data below consist of the costs of advertising (in thousands of dollars) and the number of pro sold (in thousands): Cost 7 3 Number 85 52 55 68 67 80 83 73 9 10 y = r =

Given Information: Data represents the costs of advertising and the number of products sold, where Independent variable X is the cost and Dependent variable Y is the number of products sold. General form of regression equation is y^=a+bx where, a is the intercept and b is the slope. Slope is given by the formula: b=n∑ixy-∑ix∑iyn∑ix2-∑ix2 Calculations: Substitute the values in the formula: b=n∑ixy-∑ix∑iyn∑ix2-∑ix2=8×3147-42×5638×288-422=25176-236462304-1764=1530540=2.833333333≈2.83 Intercept is given by the formula: a=y¯-bx¯ where, y¯=5638=70.375 and x¯=428=5.25 Substitute in the formula: a=y¯-bx¯=70.375-2.8333333335.25=55.5 Therefore, regression equation can be written as follows: y^=a+bxy^=55.5+2.83x b) Correlation coefficient is obtained using the formula: r=n∑ixy-∑ix∑iyn∑ix2-∑ix2n∑iy2-∑iy2=8×3147-42×5638×288-4228×40685-5632=1530540×8511=15302143.814358=0.7136811983≈0.71 Thus, correlation coefficient r is 0.71