# hw1 - deviation(d(8 points From the R output of(a write...

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STAT 4220 HW1 (30 points) Due on Thu, January 28 1. Consider an old economic dataset on 50 diﬀerent countries. This dataset is within the faraway library. These data are averages over 1960 - 1970 (to remove business cycle or other short-term ﬂuctuations). dpi is per-capita disposable income in U.S. dollars; ddpi is the percent rate of change in per capita disposable income; sr is aggregate personal saving divided by disposable income. The percentage population under 15 ( pop15 ) and over 75 ( pop75 ) are also recorded. The data come from Belsley, Kuh, and Welsch (1980). Take a look at the data. > data(savings) > savings (a) (7 points) First ﬁt a model with all the predictors. Take sr as the response variable. Write down the R code and give the R output as I have done in the lecture notes. (b) (3 points) Write down the null and alternative corresponding to the p-value 0.002603 (from the R output of (a)). What is your conclusion? (c) (2 points) From the R output of (a), ﬁnd the estimate of model standard
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Unformatted text preview: deviation. (d) (8 points) From the R output of (a), write down the ANOVA table. Show all steps (as I did on the board). 2. Consider the following dataset. You have to enter the data manually. item x1 x2 x3 y 1 60.323 159.0 235.6 1947 2 61.122 145.6 232.5 1948 3 60.171 161.6 368.2 1949 4 61.187 165.0 335.1 1950 5 63.221 309.9 209.9 1951 6 63.639 359.4 193.2 1952 7 64.989 354.7 187.0 1953 8 63.761 335.0 357.8 1954 9 66.019 304.8 290.4 1955 10 67.857 285.7 282.2 1956 11 68.169 279.8 293.6 1957 12 66.513 263.7 468.1 1958 13 68.655 255.2 381.3 1959 14 69.564 251.4 393.1 1960 15 69.331 257.2 480.6 1961 16 70.551 282.7 400.7 1962 (a) (8 points) Fit a regression model with no intercept using the command > g = lm(y~x1+x2+x3-1) > summary(g) (b) (2 points) The value of multiple R 2 is 0.9989. So can you conclude that this is a very good ﬁt? 1...
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## This note was uploaded on 06/06/2011 for the course STAT 4220 taught by Professor Smith during the Spring '08 term at UGA.

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