The scatterplot and the model in Fig. 63 compare the annual amounts (in millions of pounds) of herbicides used with the numbers (in millions) of bee colonies in the United States for years between 1939 and 2013, inclusive.

a. Is the association positive, negative, or neither? What does it mean in this situation?
b. Estimate the slope of the model. What does it mean in this situation?
c. If the amount of herbicides used in a certain year was 300 million pounds more than in another year, estimate how many fewer colonies of bees there were in the year when more herbicides were used.
d. On the basis of the scatterplot, a student concludes that herbicides kill bees. What would you tell the student?

Herbicides versus Bee Colonies 0 100 200 300 400 500 600 Herbicides (millions of pounds)