advertising firm wishes to demonstrate to its clients the effectiveness of the advertising campaigns it has conducted. The following bivariate data on twe ent campaigns, induding the cost of each campaign (in millions of dollars) and the resulting percentage increase in sales following the campaign, were sented by the firm. Based on these data, we would compute the least-squares regression line to be y = 6.15 +0.19x, with x representing campaign cos presenting the resulting percentage increase in sales. (This line is shown below, along with a scatter plot of the data.) Campaign cost, x Increase in sales, y (in millions of dollars) (percent) 1.99 6.74 7.2 3.93 6.98 3.96 6.78 1.63 6.63 6.8 3.08 6.55 6.6- (percent) Increase in sales 1.63 6.20 6.4 _ 2.88 6.61 2.38 6.63 3.00 6.91 1.35 6.33 3 35 3.63 6.83 Campaign cost (in millions of dollars) 2.13 6.49 end data to calculator the firm's data and the regression line, complete the following. For these data, values for campaign cost that are less than the mean of the values for campaign cost tend to be paired with values for percentage increase in sales that are (Choose one) V the mean of the values for percentage ncrease in sales