1. A new type of screening for lung cancer , CT, has been developed. Medical researchers believe that CT scans are more sensitive than regular X-rays in pinpointing small tumors. A university is conducting a medical trial of 50,000 smokers nationwide to compare the effectiveness of CT scans with X-rays for detecting lung cancer... One goal of the study is to compare the mean ages when cancer is first detected by the two screening methods.
2. A study of Machiavellian traits in consultants was performed... The consultants were then classified as having dishonest, neutral, or honest Mach rating scores. The researcher investigated the impact of both Mach score and gender on the average income of a consultant.
3. Consider the dot plots A and B.
Plot A: Sample 1: 6,7,8,8,9,10 Sample 2: 12,13,14,14,15,16
Plot B: Sample 1: 5,5,7,11,13,13 Sample 2: 10,12,12,16,16,18
Plot A:
|
Source
|
df
|
SS
|
MS
|
F
|
|
Treatment
|
1
|
108
|
108
|
54
|
|
Error
|
10
|
20
|
2
|
|
|
Total
|
11
|
128
|
|
|
Plot B:
|
Source
|
df
|
SS
|
MS
|
F
|
|
Treatment
|
1
|
75
|
75
|
6.25
|
|
Error
|
10
|
120
|
12
|
|
|
Total
|
11
|
195
|
|
|
4. The partially completed ANOVA table for a 3x4 factorial experiment with two replications is shown below:
|
Source
|
df
|
SS
|
MS
|
F
|
|
A
|
-
|
0.3
|
-
|
-
|
|
B
|
-
|
3.9
|
-
|
-
|
|
AB
|
-
|
9.6
|
-
|
-
|
|
Error
|
-
|
-
|
-
|
|
|
Total
|
-
|
18.7
|
|
|
5. The table for problem 5 was missing, so we didn't have to complete problem 5.
6. What conditions must n satisfy to make the x^2 test valid?
n must be large enough so that for every cell the expected cell count will be equal to 5 or more.
7. The table to the right gives the breakdown of the root causes of a sample of 87 industrial accidents. Are there significant differences in the percentage of incidents in the four cause categories? Use a=0.05.
|
System Cause
|
Number of Incidents
|
|
Design
|
29
|
|
Procedures
|
23
|
|
Management
|
22
|
|
Training
|
13
|
|
Total
|
87
|
Determine the null and alternative hypothesis for this test.
Ho:p1=p2=p3=p4=0.25
8. Find the rejection region for a test of independence of two classifications where the contingency table contains r rows and c columns.
a. a=0.05, r=3, c=6
b. a=0.10, r=6, c=3.
c. a=0.01, r=2, c=5.
9. Test the null hypothesis of independence of the two classifications A and B of accompanying contingency table. Use a=0.05.
| |
B1
|
B2
|
B3
|
|
A1
|
42
|
71
|
44
|
|
A2
|
63
|
53
|
70
|
|
A3
|
31
|
37
|
30
|
Specify the null and alternative hypothesis.
Ho: The row and column classifications are independent.
Ha: The row and column classifications are dependent.
Find the test statistics.
X^2=10.57.
Specify the rejection region.
X^2>9.48773.
State the conclusion.
Reject Ho; there is sufficient evidence to indicate the row and column classification are dependent at a=0.05.
10. Which term below refers to the descriptors of variables computed from sample data used to estimate those same variables in the population?
Sample statistics.
11. Which term below refers to a controlled, randomized procedure that assures that each population element is given a known, nonzero chance of selection into a study's sample?
Probability sampling.
12. When selecting a convenience sample , element selection is based on.
Accessibility.
13. Involves assigning numbers or other symbols to answers so that the responses can be grouped into a limited number of categories.
Coding.
14. Which type of chart uses bars to represent data values such that each value occupies an equal amount of area within an enclosed area?
Histogram.