The following set of ordered pairs gives the results of a science exper- iment. Twelve people were given different daily doses of vitamin C, in milligrams, for a year. This is the x-value. They reported the num- ber of colds they got during the year. This is the y-value.
(100, 4), (100, 4), (100, 3), (250, 3), (250, 2), (250, 2),
(500, 1), (500, 2), (500, 1), (1,000, 1), (1,000, 2), (1,000, 1)
a. Construct a scatterplot.
b. Describe the correlation.
c. Should the scientists label the vitamin C intake the explanatory variable and the number of colds the response variable? Explain.