Regular gas. The data set provided contains U.S.

regular retail gasoline prices (cents/gallon) from August 20, 1990 to May 28, 2007, from a national sample of gasoline stations obtained from the U.S. Department of Energy.

a) Create a histogram of the data and describe the distribution.

b) Create a time series plot of the data and describe the trend.

c) Which graphical display seems the more appropriate for these data? Explain.