25. a.
, so reject H .
b.
.1056
c.
217
27. a.
. A box- plot shows substantial positive skew; there are no outliers.
b.
No. A normal probability plot shows substantial curva- ture. No, since n is large.
c.
; reject H at any reasonable significance
level; yes.
d.
.821
29. a.
No, since
b.
.30 from software
31.
No, since
33. a.
No, since
b.
Yes, type II
c.
.66 from software
37. a.
No, since
b.
I: say that more than 20 are obese when this is not the case; II: conclude that 20 are obese when the actual
percentage exceeds 20.
c.
.121
39.
, so reject . No.
41. a. z
1.0, so there is not enough evidence to conclude that
thus, use screwtops.
b.
I: Don’t use screwtops when their use is justified; II: Use screwtops when their use isn’t justified.
43. a.
, reject H and the company’s premise.
b.
.0332
45.
No, no, yes.
47. a.
Reject H .
b.
Reject H .
c.
Don’t reject H .
d.
Reject H . a close call
e.
Don’t reject H .
49. a.
.0778
b.
.1841
c.
.0250
d.
.0066
e.
.5438
51. a.
.040
b.
.018
c.
.130
d.
.653
e. f.
.000 ,
.005 R 5
55, 6, c
, 24, 25 6, a 5 .098, b 5 .090
z 5 3.07 2.58
p , .25;
2 5
H : p 5 .40
z 5 3.67 2.58
1.28 , 1.645 2.44 , 2.539
1.04 , 2.132 1.19 , 1.796
z 5 2 5.79
x 5 .750, x| 5 .640, s 5 .3025, f
s
5 .480
z 5 2 3.33 22.58
53.
, so don’t reject H ; no apparent difference.
55.
, so should be rejected in
favor of .
57.
No, since
59. a. Yes b. The P-value slightly exceeds .10, so
should not be rejected, and the concrete should be used.
61.
, so . H
should therefore not be rejected.
63. a.
.8980, .1049, .0014
b.
. Yes.
c.
No
65.
, so H should be rejected.
67. a.
versus
b. H
cannot be rejected for either a.
69. a.
No, because ; yes, because 45.31
greatly exceeds 20, but n is very small.
b. 71. a.
No; no
b.
No, because and
.
73. a.
Approximately .6; approximately .2 from Appendix Table A.17
b. 75. a.
, so H cannot be rejected; Type II
b.
.10. Yes.
77.
Yes. , so
H should be rejected.
79.
No, since .
81.
Yes, since and
83. a.
, so do not reject H ; no contradiction
85. a.
For , reject
H if
b.
, so do not reject H .
87. a.
Yes, a 5 .002 Test statistic value 5 19.65 . 8.260
2 g
x
i
m x
12a, 2n 2
H
a
: m , m .01 , P-value , .025
P -value 5 0 , .05
z 5 4.4
z 5 1.33 , 2.05
z 5 2 3.32 23.08
z 5 1.64 , 1.96
n 5 28
P -value 5 .33 . .10
z 5 .44
b 5 .3 software
P -value 5 .02 . .01
H
a
: m 2 .85 H
: m 5 .85 z 5 2
3.12 21.96 P
-value 0 P
-value .116 t
1.9 H
: m 5 100 P
-value 5 .2266 H
a
: m 2 5 H
: m 5 5 P
-value , .0004 , .01 P
-value . a
Chapter 9
1. a.
; it doesn’t
b.
.0724, .2691
c.
No
3.
, so don’t reject H .
5. a.
, so reject H .
b.
.0019
c.
.8212
d.
66
7.
No, since P-value for a 2-tailed test is .0602.
9. a.
6.2; yes
b.
, , no
c.
No
d.
A 95 CI is 10.0, 21.8.
11.
A 95 CI is .99, 2.41.
13.
50
15. b.
It increases.
17. a.
17
b.
21
c.
18
d.
26
19.
, so do not reject H .
t 5 2 1.20 . 2t
.01,9
5 2 2.821
P -value .25
z 5 1.14
z 5 2 2.90
z 5 1.76 , 21.33
2 .4 hr
21.
Yes; , so reject H
.
23. b.
No
c.
for any reasonable a, so don’t reject
.
25.
.3, 6.1, yes, yes
27. a.
99 CI: .33, .71
b.
99 CI: , so 0 is a
plausible value of the difference.
29.
. At significance level .05, we would conclude that cola results in a higher average
strength, but not at significance level .01.
31. a.
Virtually identical centers, substantially more variability in medium range observations than in higher range obser-
vations
b.
, based on 23 df; no 27.9, 9.6
t 5 2 2.10, df 5 25, P-value 5 .023
2.07, .41 H
P-value .7 t 5 2
.38 . 2t
a 2, 10
2 2.64 22.602
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook andor eChapters. Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
Kategori