Constant $51,999.64 7,968.68 6.51 Independent variable: Online advertising expense 0.98 199 - = 0.02; DurbineWatson statistic = 214 2. Plot the preceding data on a graph and draw the regression line. What does the cost formula indicate about the relationship between monthly online advertising expense and monthly sales revenue? Is the elationship economically plausible? 3. After further thought, Nandita realizes there may have been a flaw in her approach In particular, there may be a lag between the time customers click through to the Modus website and peruse its social media content (which is when the online ad expense is incurred) and the time they actually shop in the physical store. Nandita modifies her analysis by comparing each month's sales revenue to the advertising expense in the prior month After discarding September sales revenue and August advertising expense, show that the modified regression yields the following Sales revenue = $28,361.37 + (5.38 x Online advertising expense) Variable Coefficient Standard Error t-Value $28,361.37 5,425.69 5.2 ent variable: Previous month's online advertising expense 5.38 0.65; Durbin-Watson statistic = 1 4. What does the revised formula indicate? Plot the revised data on a graph. Is this relationship economically plausible? 5. Can Nandita conclude that there is a cause-and effect relationship between online advertising expense and sales revenue? Why or why