Stat 512 – 1
Homework #5
Dr. Levine
Due Friday, Oct23rd
For the following group of problems use the computer science data that we have been discussing
in class.
The variables are:
id
, a numerical identifier for each student;
GPA
, the grade point
average after three semesters;
HSM; HSS; HSE; SATM; SATV,
which were all explained
in class; and
GENDER
, coded as 1 for men and 2 for women.
1.
In this exercise you have to illustrate some of the ideas described in Chapter 7 of the text
related to the extra sums of squares.
Create a new variable called
SAT
which equals
SATM + SATV
and run the following two regressions:
(i)
predict
GPA
using
HSM
,
HSS
, and
HSE
;
(ii) predict
GPA
using
SAT
,
HSM
,
HSS
and
HSE
.
Calculate the extra sum of squares for the comparison of these two analyses. Use it to
construct the F statistic (i.e., general linear test statistic) for testing the null hypothesis that
the coefficient of the
SAT
variable is zero in the model with all four predictors. What are
the degrees of freedom for this test statistic?
Use the
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 Spring '08
 Staff
 Regression Analysis, explanatory variables, fitted regression line, explanatory variable HSM, explanatory variable HSS

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