A sample was taken of the salaries of 20 employees of a large company. The following are the salaries (in thousands of dollars) for this year. For convenience, the data are ordered.
28
31
34
35
37
41
42
42
42
47
49
51
52
52
60
61
67
72
75
77


1.
The median salary of the 20 employees is
A.
$49,000.
B.
$48,000.
C.
$47,000.
D.
$42,000.


2.
Suppose each employee in the company receives a $3000 raise for next year (each employee's salary is increased by $3000). The median salary for the employees working for the company will
A.
be unchanged.
B.
increase by $3000.
C.
be multiplied by $3000.
D.
increase by .


3.
A set of data has a median that is much larger than the mean. Which of the following statements is most consistent with this information?
A.
A stemplot of the data is symmetric.
B.
A stemplot of the data is skewed left.
C.
A stemplot of the data is skewed right.
D.
The data set must be so large that it would be better to draw a histogram than a stemplot.


4.
A reporter wishes to portray baseball players as overpaid. Which measure of center should he report as the average salary of major league players?
A.
The mean.
B.
The median.
C.
Either the mean or median. They will be equal in this case.
D.
Neither the mean nor the median. Both will be much lower than the actual average salary.


A sample was taken of the salaries of 20 employees of a large company. The following are the salaries (in thousands of dollars) for this year. For convenience, the data are ordered.
28
31
34
35
37
41
42
42
42
47
49
51
52
52
60
61
67
72
75
77


5.
The first quartile of the 20 salaries is
A.
$35,000.
B.
$36,000.
C.
$37,000.
D.
$39,000.


6.
This is a standard deviation contest. Which of the following sets of four numbers has the largest possible standard deviation?
A.
7, 8, 9, 10
B.
5, 5, 5, 5
C.
0, 0, 10, 10
D.
0, 1, 2, 3


7.
The rental values (in dollars) of a sample of four available apartments close to the university are
470
600
580
550

The standard deviation of the sample is
A.
$30.31.
B.
$35.00.
C.
$57.15.
D.
$49.50.


The distribution of actual weights of 8.0 oz. chocolate bars produced by a certain machine is normal with a mean of 8.1 oz. and a standard deviation of 0.1 oz.


8.
The proportion of chocolate bars weighing under 8.0 oz. is
A.
0.500.
B.
0.159.
C.
0.341.
D.
0.841.


9.
The proportion of chocolate bars with weights between 8.2 and 8.3 oz. is
A.
0.819.
B.
0.636.
C.
0.477.
D.
0.136.


The temperature at any random location in a kiln used in the manufacture of bricks is normally distributed with a mean of 1000 and a standard deviation of 50° F.


10.
If bricks are fired at a temperature above 1125° F, they will crack and must be disposed of. If the bricks are placed randomly throughout the kiln, the proportion of bricks that crack during the firing process is closest to
A.
49.38%.
B.
2.28%.
C.
47.72%.
D.
0.62%.


11.
When glazed bricks are put in the oven, if the temperature is below 900° F they will miscolor. If the bricks are placed randomly throughout the kiln, the proportion of glazed bricks that miscolor is closest to
A.
49.38%.
B.
2.28%.
C.
47.72%.
D.
0.62%.


12.
The stores of a large retail chain were divided into three groups. While customers were shopping, group 1 played light rock music, group 2 played classical music, and group 3 played show tunes. The daily sales for each day in a 30-day period were recorded. Suppose that, on average, sales were highest in those stores that played light rock music, second highest for those stores playing show tunes, and lowest for those stores playing classical music. We conclude
A.
there is a positive association between sales and type of music played.
B.
there is a negative association between sales and type of music played.
C.
there is both positive and negative association present.
D.
none of the above.


13.
A college newspaper interviews a psychologist about a proposed system for rating the teaching ability of faculty members. The psychologist says, “The evidence indicates that the correlation between a faculty member's research productivity and teaching rating is close to zero.” A correct interpretation of this statement would be
A.
good researchers tend to be poor teachers and vice versa.
B.
good teachers tend to be poor researchers and vice versa.
C.
good researchers are just as likely to be good teachers as they are bad teachers. Likewise for poor researchers.
D.
good research and good teaching go hand in hand.


14.
A study found a correlation of r = –0.61 between the gender of a worker and his or her income. You may correctly conclude that
A.
women earn more than men on the average.
B.
women earn less than men on the average.
C.
an arithmetic mistake was made. Correlation must be positive.
D.
this is incorrect because r makes no sense here.


I wish to determine the correlation between the height (in inches) and weight (in pounds) of 21-year-old males. To do this I measure the height and weight of two 21-year-old men. The measured values are
 
Male #1
Male #2
Height
70
75
Weight
160
200
 


15.
The correlation r computed from the measurements on these males is
A.
1.0.
B.
positive and between 0.25 and 0.75.
C.
near 0, but could be either positive or negative.
D.
exactly 0.


16.
The correlation r would have units
A.
inches.
B.
pounds.
C.
inches-pounds.
D.
no units. Correlation is a unitless quantity.


John's parents recorded his height at various ages up to 66 months. Below is a record of the results
Age (months)
36
48
54
60
66
Height (inches)
35
38
41
43
45
 


17.
Which of the following is the equation of the least-squares regression line of John's height on age? (NOTE: You do not need to directly calculate the least-squares regression line to answer this question.)
A.
Height = 12 × (Age)
B.
Height = Age/12
C.
Height = 60 – 0.22 × (Age)
D.
Height = 22.3 + 0.34 × (Age)


18.
John's parents decide to use the least-squares regression line of John's height on age to predict his height at age 21 years (252 months). We conclude
A.
John's height, in inches, should be about half his age, in months.
B.
that the parents will get a fairly accurate estimate of his height at age 21 years, because the data are clearly correlated.
C.
such a prediction could be misleading, because it involves extrapolation.
D.
all of the above.


19.
The least-squares regression line is
A.
the line that makes the square of the correlation in the data as large as possible.
B.
the line that makes the sum of the squares of the vertical distances of the data points from the line as small as possible.
C.
the line that best splits the data in half, with half of the points above the line and half below the line.
D.
all of the above.


20.
A researcher notices that in a sample of adults, those who take larger amounts of vitamin C have fewer illnesses. However, those who take larger amounts of vitamin C also tend to exercise more. As explanations for having fewer illnesses, the variables “amount of vitamin C taken” and “amount of exercise” are
A.
skewed.
B.
confounded.
C.
lurking variables.
D.
symmetric.


A business has two types of employees: managers and workers. Managers earn either $100,000 or $200,000 per year. Workers earn either $10,000 or $20,000 per year. The number of male and female managers at each salary level and the number of male and female workers at each salary level are given in the two tables below.
 
Managers
 
Workers
 
Male
Female
 
 
Male
Female
$100,000
80
20
 
$10,000
30
20
$200,000
20
30
 
$20,000
20
80
 


21.
The proportion of male managers who make $200,000 per year is
A.
0.067.
B.
0.133.
C.
0.200.
D.
0.400.


22.
We may conclude
A.
the mean salary of female managers is greater than that of male managers.
B.
the mean salary of males in this business is greater than the mean salary of females.
C.
the mean salary of female workers is greater than that of male workers.
D.
all of the above.


You need to select a simple random sample of three from the following employees of a small company.
1. Bechhofer
4. Kesten
7. Taylor
2. Brown
5. Kiefer
8. Wald
3. Ito
6. Spitzer
9. Weiss

Using the numerical labels attached to the names above and the following list of random digits. Read the list of random digits from left to right, starting at the beginning of the list.

11793 20495 05907 11384 44982 20751 27498 12009 45287 71753 98236 66419 84533


23.
The simple random sample is
A.
117.
B.
Bechhofer, then Bechhofer again, then Taylor.
C.
Bechhofer, Taylor, Weiss.
D.
Kesten, Kiefer, Taylor.


24.
Which of the following statements is true?
A.
If we used another list of random digits to select the sample, we would get the same result as obtained with the list actually used.
B.
If we used another list of random digits to select the sample, we would get a completely different sample than that obtained with the list actually used.
C.
If we used another list of random digits to select the sample, we would get at most one name in common with that obtained with the list actually used.
D.
If we used another list of random digits to select the sample, the result obtained with the list actually used would be just as likely to be selected as any other set of three names.


25.
A stratified random sample corresponds to which of the following experimental designs?
A.
A block design.
B.
A double blind experiment.
C.
A experiment with a placebo.
D.
A confounded, nonrandomized study.


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