Care must be taken when making predictions by extrapolating from known data, especially when the data set is as small as the one in Example 1.3.8. In particular, the economy began to weaken after the year 2000, but the least- squares line in Figure 1.29 predicts a steadily decreasing unemployment rate. Is this reasonable? In Exercise 48, you are asked to explore this question by using unemployment data from 2001 to 2009 and then comparing these new data with the values predicted by the least-squares line.