For each of the following studies, identify the type of graph (histogram, time series graph, or scatter diagram) that would be the most appropriate. (You can use more than one graph of each type, for example, two histograms.)

a. Has air pollution in Los Angeles generally risen or fallen during the past 20 years?

b. Do colleges that accept a large percentage of their students in early-decision programs have higher yields (percentage of accepted students who enroll)?

c. Can college grade point averages be predicted from high school grade point averages?

d. Do students who get more sleep get higher grades?

e. Is there more dispersion in the starting salaries of economics majors or English majors?