Download Practice problem 2

Practice problem 2
DS-203
Fall 2005
1. A consumer group surveyed the prices for a certain item in five different stores and
reported the average price as $15. We visited four of the five stores and found the
prices to be $10, $15, $15, and $25. Assuming that the consumer group is correct, what
is the price of the item at the store that we did not visit?
A) $10
B) $15
C) $20
D) $25
2. The average salary of all female workers is $35,000. The average salary of all male
workers is $41,000. What must be true about the average salary of all workers?
A) It must be $38,000.
B) It must be larger than the median salary.
C) It could be any number between $35,000 and $41,000.
D) It must be larger than $38,000.
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
49
31
51
3.
A)
B)
C)
D)
34
52
35
52
37
60
41
61
42
67
42
72
The median salary of the 20 employees is
$49,000.
$48,000.
$47,000.
$42,000.
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42
75
47
77
4. 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 $3000 .
5. The numbers of new projects started each month at an advertising agency for the last six
months are
2
5
3
3
6
3
A)
B)
C)
D)
The interquartile range for the above data is
1.0.
4.0.
5.0.
2.0.
6.
A)
B)
C)
D)
The five-number summary of a set of data is
the minimum, first quartile, median, third quartile, and maximum.
the mean, median, mode, variance, and standard deviation.
any five-digit number that describes the data.
any five single-digit numbers that are measures of center and spread.
7. 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
8.
A)
B)
C)
D)
A normal density curve has which of the following properties?
It is symmetric.
It has a peak centered above its mean.
The spread of the curve is proportional to the standard deviation.
All of the above.
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.
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9. 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%.
10. 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%.
11. A company produces packets of soap powder labeled “Giant Size 32 Ounces”. The
actual weight of soap powder in a box has a normal distribution, with a mean of 33 oz.
and a standard deviation of 0.7 oz. What proportion of packets are underweight (i.e.,
weigh less than 32 oz.)?
A) .0764
B) .2420
C) .7580
D) .9236
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Answer Key
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
A
C
B
B
D
A
C
D
D
B
A
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