ID Year CornYield SoyBeanYield
1 1957 48.3 23.2
2 1958 52.8 24.2
3 1959 53.1 23.5
4 1960 54.7 23.5
5 1961 62.4 25.1
6 1962 64.7 24.2
7 1963 67.9 24.4
8 1964 62.9 22.8
9 1965 74.1 24.5
10 1966 73.1 25.4
11 1967 80.1 24.5
12 1968 79.5 26.7
13 1969 85.9 27.4
14 1970 72.4 26.7
15 1971 88.1 27.5
16 1972 97 27.8
17 1973 91.3 27.8
18 1974 71.9 23.7
19 1975 86.4 28.9
20 1976 88 26.1
21 1977 90.8 30.6
22 1978 101 29.4
23 1979 109.5 32.1
24 1980 91 26.5
25 1981 108.9 30.1
26 1982 113.2 31.5
27 1983 81.1 26.2
28 1984 106.7 28.1
29 1985 118 34.1
30 1986 119.4 33.3
31 1987 119.8 33.9
32 1988 84.6 27.0
33 1989 116.3 32.3
34 1990 118.5 34.1
35 1991 108.6 34.2
36 1992 131.5 37.6
37 1993 100.7 32.6
38 1994 138.6 41.4
39 1995 113.5 35.3
40 1996 127.1 37.6
41 1997 126.7 38.9
42 1998 134.4 38.9
43 1999 133.8 36.6
44 2000 136.9 38.1
45 2001 138.2 39.6
46 2002 129.3 38.0
47 2003 142.2 33.9
48 2004 160.3 42.2
49 2005 147.9 43.1
50 2006 149.1 42.9
51 2007 150.7 41.7
Use both predictors. From the previous twoexercises, we conclude that year and soybean may be useful togetherin a model for predicting corn yield. Run this multipleregression.
a) Explain the results of the ANOVA F test. Give the null andalternate hypothesis, test statistic with degrees of freedom, andp-value. What do you conclude?
b) Whatpercent of the variation in corn yield in explained by these twovariables? Compare it with the percent explained in the previoussimple linear regression models.
c) State the regression model. Why do the coefficients for year andsoybean differ from those in the previous exercises?
d) Summarize the significance test results for the regressioncoefficients for year and soybean yield.
e) Givea 95% confidence interval for each of these coefficients.
f) Plot the residualversus year and soybean yield. What do you conclude?
