A publisher of college textbooks conducted a study to relate profit per text y to cost of sales x over a 6-year period when its sales force (and sales costs) were growing rapidly. These inflation-adjusted data (in thousands of dollars) were collected: 
Expecting profit per book to rise and then plateau, the publisher fitted the model 
to the data. What conclusions can you draw from the accompanying residual plots? 
Definitions:
Harlem Shake
A viral Internet meme and dance craze that originated in 2013, featuring an excerpt from the song "Harlem Shake" and videos of people dancing in a comedic manner.
Mass Behavior
Similar behaviors engaged in by large groups of people without their necessarily being in the same place.
Contagion Theory
One of the earliest theories of collective action; suggests that individuals who join a crowd can become “infected” by a mob mentality and lose the ability to reason.
Collective Behavior
Behavior that follows from the formation of a group or crowd of people who take action together toward a shared goal.
Q6: Which of the following statements is false?<br>A)
Q35: The statistic <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB8220/.jpg" alt="The statistic
Q38: Six points have these coordinates: <img src="https://d2lvgg3v3hfg70.cloudfront.net/TB8220/.jpg"
Q56: In regression analysis, the dependent variable is
Q78: If all the points in a scatterplot
Q119: Nonparametric statistical methods generally specify hypotheses in
Q131: The nonparametric tests discussed in your book
Q135: The method of least squares requires that
Q175: In a Wilcoxon rank sum test, the
Q189: The sampling distribution used to make inferences