An article that appeared in USA Today ( September 3, 2003) included a graph similar to the one shown here summarizing responses from polls conducted in 1978, 1991, and 2003, in which samples of American adults were asked whether or not it was a good time or a bad time to buy a house.

a. Construct a time series plot that shows how the percent-age that thought it was a good time to buy a house has changed over time.
b. Add a new line to the plot from Part (a) showing the percentage that thought it was a bad time to buy a house over time. Be sure to label the lines.
c. Which graph, the given bar chart or the time series plot, best shows the trend over time?

Mar-78 Mar-91 Jun-03 Sep-03 90% - 80% 70% 60% 53% 50% 40% 30% 20% 10% - 0% L 78% 78% 67% 29% 25% 19% 20% Good time Bad time