Table 1. Annual U.S. GDP and %Change

	Year	GDP	% Change	Year	GDP	% Change
	1975	4084.4		1988	6368.4	4.17
	1976	4311.7	5.57	1989	6591.8	3.51
	1977	4511.8	4.64	1990	6707.9	1.76
	1978	4760.6	5.51	1991	6676.4	-0.47
	1979	4912.1	3.18	1992	6880	3.05
	1980	4900.9	-0.23	1993	7062.6	2.65
	1981	5021	2.45	1994	7347.7	4.04
	1982	4919.3	-2.03	1995	7543.8	2.67
	1983	5132.3	4.33	1996	7813.2	3.57
	1984	5505.2	7.27	1997	8159.5	4.43
	1985	5717.1	3.85	1998	8515.7	4.37
	1986	5912.4	3.42	1999	8875.8	4.23
	1987	6113.3	3.40

95% confidence interval for the population average of the %Change in GDP.

n = 24

c = 0.95

a = 1-c a = 1-0.95 a = 0.05

x bar = 3.306

sample standard deviation= 2.0083

df=n1 df=241 df=23

tc=t(/2)=2.069

Distribution Plot T, df=23 0.4 0.3 Density 0.2 0.1- 0.025 0.025 0.0 -2.069 2.069 XO