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Practice Exam Questions and Solutions for the
Final Exam; Fall, 2008
Statistics 301, Professor Wardrop
Part B, Chapters 16, 8 and 13
Chapter 16
1. Independent random samples are selected from
two populations. Below are selected summary
statistics.
Pop.
Mean
Stand. Dev.
Sample size
1
62.00
10.00
17
2
54.00
6.00
10
(a) Calculate
s
p
.
(b) Calculate the 90% CI for
μ
X
−
μ
Y
. Use
Case 1.
2. Independent random samples are selected from
two populations. Below are selected summary
statistics.
•
¯
x
= 22
.
50
,
s
X
= 3
.
75
and
n
1
= 18
•
¯
y
= 16
.
25
,
s
Y
= 8
.
50
and
n
2
= 6
(a) Calculate
s
p
.
(b) Calculate the 98% CI for
μ
X
−
μ
Y
. Use
Case 1.
3. The null hypothesis is
μ
X
=
μ
Y
. Use Case 1
from Section 16.2 to obtain the Pvalue for each
of the situations described below.
(a) The alternative is
μ
X
> μ
Y
; the value of
the test statistic is 1.840; the sample sizes
are 5 and 5.
(b) The alternative is
μ
X
< μ
Y
; the value
of the test statistic is
−
3
.
150
; the sample
sizes are 6 and 7.
(c) The alternative is
μ
X
n
=
μ
Y
; the value of
the test statistic is 1.341; the sample sizes
are 5 and 12.
(d) The alternative is
μ
X
n
=
μ
Y
; the value
of the test statistic is
−
0
.
641
; the sample
sizes are 12 and 12.
4. The null hypothesis is
μ
X
=
μ
Y
. Use Case 1
from Section 16.2 to obtain the Pvalue for each
of the situations described below.
(a) The alternative is
μ
X
> μ
Y
; the value of
the test statistic is 0.690; the sample sizes
are 4 and 4.
(b) The alternative is
μ
X
< μ
Y
; the value
of the test statistic is
−
1
.
796
; the sample
sizes are 6 and 7.
(c) The alternative is
μ
X
n
=
μ
Y
; the value of
the test statistic is 1.850; the sample sizes
are 7 and 14.
(d) The alternative is
μ
X
n
=
μ
Y
; the value
of the test statistic is
−
3
.
641
; the sample
sizes are 4 and 12.
5. Mike performs a study with
n
1
= 10
and
n
2
=
6
. Using Case 1 from Section 16.2, he calcu
lates an 80% CI for
μ
X
−
μ
Y
and obtains:
[6
.
000
,
14
.
000]
.
Calculate the 95% CI for
μ
X
−
μ
Y
for Mike’s
data.
6. Maria performs a study with
n
1
= 14
and
n
2
= 12
. Using Case 1 from Section 16.2, she
calculates a 90% CI for
μ
X
−
μ
Y
and obtains:
[9
.
500
,
18
.
500]
.
Calculate the 99% CI for
μ
X
−
μ
Y
for Maria’s
data.
Chapter 8
7. Below is the table of population counts for a dis
ease and its screening test. (Recall that
A
means
the disease is present and
B
means the screen
ing test is positive.) On parts (a)–(e) below, re
port your answers as a decimal to three digits of
precision, for example 0.231.
B
B
c
Total
A
108
12
120
A
c
42
698
740
Total
150
710
860
1
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View Full Document(a) What proportion of the population is free
of the disease?
(b) What proportion of the population has the
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 Fall '08
 ProfessorWardrop
 Statistics

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