Suppose a fair coin is tossed 8 times. What is the probability of flipping exactly 3 heads?
3 3 7 16
A) B) C) D)
256 8 32 21
2. A hat contains 24 names, 13 of which are female. If three names are randomly drawn
without replacement from the hat, what is the probability that at least one male name is
A) 0.918 B) 0.859 C) 0.082 D) 0.141
3. In a sample of 20 hand-held calculators, 11 are known to be nonfunctional. If 7 of the 20
calculators are selected at random without replacement, what is the probability that exactly
5 in the selection are nonfunctional? Round to the nearest thousandth.
A) 0.714 B) 0.215 C) 0.550 D) 0.636
4. A survey showed that 9% of high school football players later played football in college.
Of these, 6% went on to play professional football. Find the probability that a randomly
selected high school football player will play both collegiate and professional football.
A) 0.54% B) 15% C) 1.5% D) 0.054%
5. A traffic light follows the pattern green, yellow, red for 55, 9, and 15 seconds, respectively.
What is the probability that a driver approaching this light will find it green or yellow?
Round your answer to 2 decimal places.
A) 0.30 B) 0.02 C) 0.89 D) 0.81
6. Suppose past experience shows that 5% of school-age children in a certain geographic
region have Attention Deficit Disorder (ADD). Assume that the probability of a doctor
correctly diagnosing a child as having ADD is 77% and the probability of incorrectly
diagnosing a child as having ADD is 4%. What is the probability that a child diagnosed as
having ADD actually has the disorder?
A) 0.9600 B) 0.9615 C) 0.5033 D) 0.7700
7. The following table gives the percent of employees of the Ace Company in each of three
salary brackets, categorized by the sex of the employees. An employee is selected at
random. What is the probability that the person is male or makes less than $30,000?
Earns at Least
Earns $30,000 and Earns
Less Than Less Than at Least
$30,000 $50,000 $50,000
Male 33% 11% 5%
Female 22% 19% 10%
A) 0.71 B) 0.55 C) 0.49 D) 1.04
8. The following table gives the results of a 2005 survey of 1000 people regarding the funding
of universal health care by employers.
Favor Oppose No Opinion Total
Democrat 275 120 25 420
Republican 160 375 45 580
Total 435 495 70 1000
What is the probability that a person selected at random from this group will favor
universal health care, given that the person is a Democrat?
171 55 11 55
A) B) C) D)
200 84 40 87
9. A company has estimated that the probabilities of success for three products introduced in
the market are 1/8, 2/7, and 1/2, respectively. Assuming independence, find the probability
that none of the products is successful?
11 1 5 55
A) B) C) D)
16 56 16 56
10. The odds against a particular candidate winning an election are estimated to be 5 to 8. If
those odds are accurate, what is the probability that the candidate will win the election?
5 5 8 8
A) B) C) D)
8 13 13 5
11. Health insurance administrative costs are a concern for many companies that supply the
insurance for their employees. The information below is information gathered recently. Let
x be the average number of employees in a group health insurance plan and y be the
average administrative cost as a percentage of claims. Find the sample correlation between
x and y.
x 5 10 24 32 61
y 30 44 37 32 11
A) –0.74 B) –0.818 C) 0.669 D) 0.818
12. In a recent year, suppose 24% of Americans identified themselves as liberal, and 28% as
conservative. If 750 Americans are chosen at random, how many people who identified
themselves as liberals and how many as conservatives would you expect?
A) 240 conservative; 125 liberal
B) 125 conservative; 128 liberal
C) 75 conservative; 108 liberal
D) 210 conservative; 180 liberal
13. Last year, the personal best high jumps of college athletes in a nearby state were normally
distributed with a mean of 214 centimeters and a standard deviation of 14 centimeters.
Which is the probability that one of the athletes, randomly selected, has a personal best
between 214 and 228 centimeters?
A) 0.341 B) 0.751 C) 0.131 D) 0.241
14. In a certain normal distribution of scores, the mean is 50 and the standard deviation is 4.
Find the z-score corresponding to a score of 55.
A) 12.50 B) 13.75 C) -1.25 D) 1.25
15. A certain model of automobile has its gas mileage (in miles per gallon, or mpg) normally
distributed, with a mean of 20 mpg and a standard deviation of 3 mpg. Find the probability
that a car selected at random has gas mileage less than 16.25 mpg.
A) 0.106 B) 0.606 C) 0.394 D) 0.894
16. The following is a list of the ages of employees at Hammers, Inc. Find the mean and the
sample standard deviation of the ages of the employees. Round noninteger results to the
21 25 32 38 44 48 52 57
57 52 38 32 52 21 32 25
A) mean: 47; standard deviation: 15.3
B) mean: 35.2; standard deviation: 11.5
C) mean: 39.1; standard deviation: 12.8
D) mean: 27.4; standard deviation: 8.9
17. A professor grades students on two tests, three quizzes, and a final examination. Each test
counts the same as three quizzes and the final examination counts the same as two tests.
Maegan has test scores of 87 and 96. Maegan's quiz scores are 88, 76, and 87. Her final
examination score is 95. Find Maegan's weighted average for the course. The professor
rounds averages to the nearest integer.
A) 88 B) 91 C) 90 D) 89
18. On a certain day in July, the high temperatures in 18 European cities were recorded. The
temperatures are displayed in the table below. Construct a frequency histogram using the
data from the table.
Temperature Interval F 61-70 71-80 81-90 91-100 101-110
Frequency 1 5 6 1 5
19. At Rosa’s summer job with a research company, she must get a random sample of people
from her town to answer a question about health habits. Which of the following methods
could be used to get a random sample?
A) Selecting people randomly by computer to respond
B) Collecting responses only at work
C) Selecting the responses of every other person she meets during a week
D) Asking for people willing to take part in a study
20. Maria and Zoe are taking Biology 101 but are in different classes. Maria’s class has an
average of 78% with a standard deviation of 5% on the midterm while Zoe’s class has an
average of 83% with a standard deviation of 12%. Assume that scores in both classes
follow a normal distribution. Now suppose that Maria scored an 84 on the midterm exam
and Zoe scored an 89. Who did better relative to their class?
C) Cannot Determine
D) They performed equally