BIT 2406 HW Answers
Assignment #2
1. Problem 11.57
a.
1025339.667; 746.7623752; 1024592.904; r
2
= .999; r = .999; 99.9% of the variation
in the observations has been explained by the regression model.
b.
T = 117.134, pvalue = .000; Reject H
0
.
2. Problem 11.89
a.
There is a relationship since F = 21.13 with a pvalue of .0002
b.
b
1
= 35.2877, [19.2202,51.3553]
3.
Problem 12.6
a.
The plot of price versus size has a straight line appearance and thus the model y =
!
0
+
!
1
x
1
+
"
is appropriate. The plot of price versus rating has a straight line appearance.
The model y =
!
0
+
!
1
x
1
+
"
is appropriate.
Combining these two models, we obtain the
model y =
!
0
+
!
1
x
1
+
!
2
x
2
+
"
.
b.
The mean of the sales prices of all houses having 20 hundred square feet and a niceness
rating of 9.
c.
!
0
= mean sales price of all houses having 0 sq.ft and 0 niceness rating – meaningless
!
1
= change in mean sales price associated with each increase in house size of 100 sq.ft.,
when niceness rating stays constant.
!
2
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 Summer '07
 LLClark
 Regression Analysis, mean sales price, straight line appearance, niceness rating

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