a. Steps to create a scatter plot to identify the best model by using a graphing utility.

1. Set corresponds to the year 1900 so that corresponds to the year 1910

2. Set the window of the scatter plot as

3. Use table graph feature and enter the corresponding tabular values as shown below: Here denote the number of years after 1900 and denote the domestic gross product of United States in billions of dollars.

40	837	85	4207
45	1559	90	4853
50	1328	95	5439
55	1700	100	9817
60	1934	101	10128
65	2373	102	10470
70	2847	103	10976
75	3173	104	11713
80	3746	105	12456