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Homework 4 Solution
Chapter 9
Question 1
(b) Noting ¯
x
= 11
.
625,
¯
Y
= 16
.
4875
B
=
∑
n
i
=1
(
x
i

¯
x
)
Y
i
∑
n
i
=1
x
2
i

n
¯
x
2
= 1
.
206
A
=
¯
Y

B
¯
x
= 2
.
464
Thus the estimated regression line is
Y
= 2
.
464 + 1
.
206
x
.
Question 3
(b) Noting ¯
x
= 2
.
6667,
¯
Y
=
.
0385
B
=
∑
n
i
=1
(
x
i

¯
x
)
Y
i
∑
n
i
=1
x
2
i

n
¯
x
2
=
.
0117
A
=
¯
Y

B
¯
x
=
.
0072
Thus the estimated regression line is
Y
=
.
0072 +
.
0117
x
(c) The estimated response at
x
= 3
.
2 is
.
0446.
Question 7
Noting ¯
x
= 35
.
65,
¯
Y
= 525
.
7
B
=
∑
n
i
=1
(
x
i

¯
x
)
Y
i
∑
n
i
=1
x
2
i

n
¯
x
2
=

1
.
213
A
=
¯
Y

B
¯
x
= 568
.
94
Thus the estimated regression line is
Y
= 586
.
94

1
.
213
x
. The estimated means
for the next 5 states are 471.9, 555.6, 558.03, 564.09, 558.03 respectively.
Question 11
Noting ¯
x
= 82
.
1429,
¯
Y
= 50
.
3929
B
=
∑
n
i
=1
(
x
i

¯
x
)
Y
i
∑
n
i
=1
x
2
i

n
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This note was uploaded on 05/07/2008 for the course MATH 105 taught by Professor Michaelchrist during the Spring '04 term at University of California, Berkeley.
 Spring '04
 MichaelChrist
 Statistics, Forecasting

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