The article “Organ Transplant Demand Rises Five Times as Fast as Existing Supply” (San Luis Obispo Tribune, Feb ru ary 23, 2001) included a graph that showed the number of people waiting for organ transplants each year from 1990 to 1999. The following data are approximate values and were read from the graph in the article:

Year Number Waiting for Transplant

(in thousands)

1 (1990) 22 225 329 433 538 644 750 857 964 10 (1999) 72

a. Construct a scatterplot of the data with y number waiting for transplant and x year. Describe how the number of people waiting for transplants has changed over time from 1990 to 1999.

b. The scatterplot in Part

(a) is shaped like segment 2 in Figure 5.38. Find a transformation of x and/or y that straightens the plot. Construct a scatterplot for your transformed variables.

c. Using the transformed variables from Part (b), fit a least-squares line and use it to predict the number waiting for an organ transplant in 2000 (Year 11).

d. The prediction made in Part

(c) involves prediction for an x value that is outside the range of the x values in the sample. What assumption must you be willing to make for this to be reasonable? Do you think this assumption is reasonable in this case? Would your answer be the same if the prediction had been for the year 2010 rather than 2000? Explain.