Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
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Total
20 Pts
17 Pts
15 Pts
15 Pts
21 Pts
25 Pts
30 Pts
13 Pts
20 Pts
176 Pts
MATH 147 FINAL EXAM
Fall 2005
December 14, 2005
Name:
Section:
DIRECTIONS:
Show all work. Solutions with no work will receive NO credit. Neatness counts. All
necessary tables are provided at the end of the test.
Carry out all your calculations to at least two
digits to the right of the decimal point.
Part I
True/False
For questions 1  10 circle T for true and F for false. (2 points each)
1.
T
F
In an observational study, the effects of treatment may be confounded with the effects of
factors that got the subjects into the treatment or control group in the first place.
2.
T
F
In a histogram with a long right tail, the median is more than the average.
3.
T
F
If you perform above average on an exam and you have an even better performance on
the next exam, your overall performance on these two tests can be explained by the regression
effect.
4.
T
F
Correlation measures association. But association does not necessarily show causation.
It may only show that both variables are simultaneously influenced by some third variable.
5.
T
F
The nullhypothesis assumes that an observed difference is due to chance.
6.
T
F
If a correlation coefficient is .9 then 90% of the points are highly correlated.
7.
T
F
In 1990, four passengers were killed by crashes on commuter airlines, compared to 39
killed on scheduled carriers (like United, Delta, and so forth). These data show that if you decide
to fly, it is safer to do so on a commuter airline.
8.
T
F
Ecological correlations are based on rates of averages. They tend to overstate the strength
of an association.
9.
T
F
Selection bias was one of the reasons for the large error in the Litery Digest Poll of 1936.
10.
T
F
If the correlation coefficient between two variables is zero (
r
= 0), then there is no linear
association between the variables.
Part II
Fill in the blank
1
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For questions 11  15 complete the sentence by filling in the blank. (2 points for each blank)
11. When a simple random sample of size 151 is obtained from a population of size 1001, then the
correction factor is
.
12. A box contains three tickets with a 0 and five tickets with a 1. Eighty draws are made at random
with replacement. There are 47 1’s among the draws. The chance error is
and the SE
is
.
13. An investigator collects data on hourly wage rates for three groups of workers. Workers in group
B earn about twice as much as those in group A; workers in group C earn about $10 an hour
more than those in group A. In the blank indicate which histogram corresponds to Group A:
,
14. Two variables have a correlation coefficient of
r
= 0
.
5. If each of the data items of the first variable
are multiplied by 2, the resulting correlation coefficient is
.
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 Fall '07
 Klimko
 Math, Null hypothesis, Statistical hypothesis testing, Simple random sample

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