1) What is the critical F value for a sample of 7 observations in the numerator and 6 in the denominator? Use a two-tailed test and the 0.1 significance level. (Round your answer to 2 decimal places.)
F
formula9.mml
3) The following is sample information. Test the hypothesis that the treatment means are equal. Use the 0.01 significance level.
Treatment 1
Treatment 2
Treatment 3
7
4
4
4
5
7
6
5
6
6
4
5
(a)
State the null hypothesis and the alternate hypothesis.
H0
H1
(b)
What is the decision rule? (Round your answer to 2 decimal places.)
H0 if the test statistic is greater than H0
4) A senior accounting major at Midsouth State University has job offers from four CPA firms. To explore the offers further, she asked a sample of recent trainees how many months each worked for the firm before receiving a raise in salary. The sample information is submitted to MINITAB with the following results:
Analysis of Variance
Source
DF
SS
MS
F
Factor
5
36.39
7.28
1.92
Error
12
45.54
3.80
Total
17
81.93
Reject if F >
5) The following data are given for a two-factor ANOVA.
Treatment
Block
1
2
A
43
36
B
37
23
C
42
37
Using the .05 significance level conduct a test of hypothesis to determine whether the block or the treatment means differ.
(a)
State the null and alternate hypotheses for treatments;
H0
H1
(b)
State the decision rule for treatments. (Round your answer to 1 decimal place.)
H0 if the test statistic is greater than
H1
Also, state the decision rule for blocks.
if the test statistic is greater than
Decision: Blocks.
6) Chapin Manufacturing Company operates 24 hours a day, five days a week. The workers rotate shifts each week. Management is interested in whether there is a difference in the number of units produced when the employees work on various shifts. A sample of five workers is selected and their output recorded on each shift. At the 0.01 significance level, can we conclude there is a difference in the mean production rate by shift or by employee?
Units Produced
Employee
Day
Afternoon
Night
Skaff
35
22
31
Lum
36
26
34
Clark
23
27
35
Treece
32
21
27
Morgan
21
24
24
For treatments: Reject Ho if F > difference in the mean production rate.
Decision by employee:difference in the mean production rate.
7) A study of the effect of television commercials on 12-year-old children measured their attention span, in seconds. The commercials were for clothes, food, and toys.
Clothes
Food
Toys
27
44
61
22
49
64
46
37
57
35
56
48
28
47
63
31
42
53
17
34
48
31
43
58
20
57
47
47
51
44
51
54
(1)
Complete the ANOVA table. Use .05 significance level. (Round the SS and MS values to 1 decimal place and F value to 2 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)
Source
DF
SS
MS
F
P
Factors
.
There isin the mean attention span.
(4)
Are there significant differences between pairs of means?
Clothes have a mean attention span of at least ten minutesthe other groups.
8) When only two treatments are involved, ANOVA and the Student t test (Chapter 11) result in the same conclusions. Also, . As an example, suppose that 14 randomly selected students were divided into two groups, one consisting of 6 students and the other of 8. One group was taught using a combination of lecture and programmed instruction, the other using a combination of lecture and television. At the end of the course, each group was given a 50-item test. The following is a list of the number correct for each of the two groups. Using analysis of variance techniques, test the null hypothesis, that the two mean test scores are equal.
Lecture and
Programmed
Instruction
Lecture and
Television
14
33
12
21
26
34
25
20
16
29
14
28
21
22
(a-1)
Complete the ANOVA table. (Round SS, MS and F values to 2 decimal places.)
Source
SS
df
MS
F
Factors
in the mean test scores.
9) The city of Tucson, Arizona, employs people to assess the value of homes for the purpose of establishing real estate tax. The city manager sends each assessor to the same five homes and then compares the results. The information is given below, in thousands of dollars. Can we conclude that there is a difference in the assessors, at α = 0.05?
Assessor
Home
Zawodny
Norman
Cingle
Holiday
A
$53
$55
$48
$43
B
50
54
54
56
C
45
58
42
57
D
76
63
61
61
E
83
81
93
85
(a)
Is there a difference in the treatment means, at α = .05? (Round your answer to 2 decimal places.)
The computed F value is a difference in the treatment means.
(b)
Is there a difference in the block means, at α = .05? (Round your answer to 2 decimal places.)
The computed F is a difference in the block means.
10) Three supermarket chains in the Denver area each claim to have the lowest overall prices. As part of an investigative study on supermarket advertising, the Denver Daily News conducted a study. First, a random sample of nine grocery items was selected. Next, the price of each selected item was checked at each of the three chains on the same day. Use 0.01 level of significance.
Item
Super$
Ralph's
Lowblaws
1
$2.30
$1.23
$1.24
2
2.30
1.70
1.78
3
2.40
3.20
3.10
4
2.40
1.78
1.87
5
1.32
1.47
1.32
6
4.01
3.06
1.82
7
4.31
3.53
2.21
8
4.13
3.07
2.35
9
5.02
4.17
4.21
in the item means. There isin the store means.
1) What is the critical F value for a sample of 7 observations in the numerator and 6 in the denominator? Use a two-tailed test and the 0.1 significance level. (Round your answer to 2 decimal places.)
F
2) Arbitron Media Research Inc. conducted a study of the iPod listening habits of men and women. One facet of the study involved the mean listening time. It was discovered that the mean listening time for men was 29 minutes per day. The standard deviation of the sample of the 10 men studied was 8 minutes per day. The mean listening time for the 12 women studied was also 29 minutes, but the standard deviation of the sample was 15 minutes. At the .10 significance level, can we conclude that there is a difference in the variation in the listening times for men and women? (Round your answer to 3 decimal places.)
The test statistic is . Decision formula9.mml
3) The following is sample information. Test the hypothesis that the treatment means are equal. Use the 0.01 significance level.
Treatment 1
Treatment 2
Treatment 3
7
4
4
4
5
7
6
5
6
6
4
5
(a)
State the null hypothesis and the alternate hypothesis.
H0
H1
(b)
What is the decision rule? (Round your answer to 2 decimal places.)
H0 if the test statistic is greater than .
(c&d)
Compute SST, SSE, and SS total and complete an ANOVA table. (Round SS, MS and F values to 3 decimal places.)
Source
SS
df
MS
F
Treatments
Error
Total
(e)
State your decision regarding the null hypothesis.
H0
4) A senior accounting major at Midsouth State University has job offers from four CPA firms. To explore the offers further, she asked a sample of recent trainees how many months each worked for the firm before receiving a raise in salary. The sample information is submitted to MINITAB with the following results:
Analysis of Variance
Source
DF
SS
MS
F
Factor
5
36.39
7.28
1.92
Error
12
45.54
3.80
Total
17
81.93
Reject if F > . (Round your answer to 2 decimal places.)
At the 0.01 level of significance, is there a difference in the mean number of months before a raise was granted among the four CPA firms?
5) The following data are given for a two-factor ANOVA.
Treatment
Block
1
2
A
43
36
B
37
23
C
42
37
Using the .05 significance level conduct a test of hypothesis to determine whether the block or the treatment means differ.
(a)
State the null and alternate hypotheses for treatments;
H0
H1
(b)
State the decision rule for treatments. (Round your answer to 1 decimal place.)
H0 if the test statistic is greater than .
(c)
State the null and alternate hypotheses for blocks.
H0
H1
Also, state the decision rule for blocks.
if the test statistic is greater than .
(d&e)
Compute SST, SSB, SS total, and SSE and complete an ANOVA table. (Round SS, MS and F values to 2 decimal places.)
Source
SS
df
MS
F
Treatments
Blocks
Error
Total
(f)
Give your decision regarding the two sets of hypotheses.
Decision: Treatments.
Decision: Blocks.
6) Chapin Manufacturing Company operates 24 hours a day, five days a week. The workers rotate shifts each week. Management is interested in whether there is a difference in the number of units produced when the employees work on various shifts. A sample of five workers is selected and their output recorded on each shift. At the 0.01 significance level, can we conclude there is a difference in the mean production rate by shift or by employee?
Units Produced
Employee
Day
Afternoon
Night
Skaff
35
22
31
Lum
36
26
34
Clark
23
27
35
Treece
32
21
27
Morgan
21
24
24
For treatments: Reject Ho if F > . (Round your answer to 2 decimal places.)
For blocks: Reject Ho if F> . (Round your answer to 2 decimal places.)
Decision by shift: difference in the mean production rate.
Decision by employee: difference in the mean production rate.
7) A study of the effect of television commercials on 12-year-old children measured their attention span, in seconds. The commercials were for clothes, food, and toys.
Clothes
Food
Toys
27
44
61
22
49
64
46
37
57
35
56
48
28
47
63
31
42
53
17
34
48
31
43
58
20
57
47
47
51
44
51
54
(1)
Complete the ANOVA table. Use .05 significance level. (Round the SS and MS values to 1 decimal place and F value to 2 decimal places. Leave no cells blank - be certain to enter "0" wherever required.)
Source
DF
SS
MS
F
P
Factors
Error
Total
(2)
Find the values of mean and standard deviation. (Round the mean and standard deviation values to 3 decimal places.)
Level
N
Mean
StDev
Clothes
Food
Toys
(3)
Is there a difference in the mean attention span of the children for the various commercials?
The hypothesis of identical means can definitely be.
There is in the mean attention span.
(4)
Are there significant differences between pairs of means?
Clothes have a mean attention span of at least ten minutes the other groups.
8) When only two treatments are involved, ANOVA and the Student t test (Chapter 11) result in the same conclusions. Also, . As an example, suppose that 14 randomly selected students were divided into two groups, one consisting of 6 students and the other of 8. One group was taught using a combination of lecture and programmed instruction, the other using a combination of lecture and television. At the end of the course, each group was given a 50-item test. The following is a list of the number correct for each of the two groups. Using analysis of variance techniques, test the null hypothesis, that the two mean test scores are equal.
Lecture and Programmed Instruction
Lecture and Television
14
33
12
21
26
34
25
20
16
29
14
28
21
22
(a-1)
Complete the ANOVA table. (Round SS, MS and F values to 2 decimal places.)
Source
SS
df
MS
F
Factors
Error
Total
(a-2)
Use a level of significance. (Round your answer to 2 decimal places.)
The test statistic is F
(b)
Using the t test from Chapter 11, compute t. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)
t
(c)
There is in the mean test scores.
9) The city of Tucson, Arizona, employs people to assess the value of homes for the purpose of establishing real estate tax. The city manager sends each assessor to the same five homes and then compares the results. The information is given below, in thousands of dollars. Can we conclude that there is a difference in the assessors, at α = 0.05?
Assessor
Home
Zawodny
Norman
Cingle
Holiday
A
$53
$55
$48
$43
B
50
54
54
56
C
45
58
42
57
D
76
63
61
61
E
83
81
93
85
(a)
Is there a difference in the treatment means, at α = .05? (Round your answer to 2 decimal places.)
The computed F value is .
Decision: a difference in the treatment means.
(b)
Is there a difference in the block means, at α = .05? (Round your answer to 2 decimal places.)
The computed F is .
Decision: a difference in the block means.
10) Three supermarket chains in the Denver area each claim to have the lowest overall prices. As part of an investigative study on supermarket advertising, the Denver Daily News conducted a study. First, a random sample of nine grocery items was selected. Next, the price of each selected item was checked at each of the three chains on the same day. Use 0.01 level of significance.
Item
Super$
Ralph's
Lowblaws
1
$2.30
$1.23
$1.24
2
2.30
1.70
1.78
3
2.40
3.20
3.10
4
2.40
1.78
1.87
5
1.32
1.47
1.32
6
4.01
3.06
1.82
7
4.31
3.53
2.21
8
4.13
3.07
2.35
9
5.02
4.17
4.21
(a-9)
Is there a difference in the item means and in the store means?
There is in the item means. There is in the store means.
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