STT 2810 FINAL EXAM QUESTIONS
AND ANSWERS ALL CORRECT
The plastic arrow on a spinner for a child's game stops rotating to point at a color that
will determine what happens next. Determine whether the following probability
assignment is legitimate.
Probability of . . .
Red
Yellow
Green
Blue
0.24
0.17
0.12
0.47 - Answer- Legitimate
The plastic arrow on a spinner for a child's game stops rotating to point at a color that
will determine what happens next. Determine whether the following probability
assignment is legitimate.
Probability of . . .
Red
Yellow
Green
Blue
0.25
0.21
0.17
0.47 - Answer- Not legitimate
In a survey of American women who were asked to name their favorite color, 19% said
blue, 20% said red, 12% said green, 13% said yellow, 36% said black, and the rest
named another color. If you pick a survey participant at random, what is the probability
that her favorite color is yellow or black? - Answer- .49
A consumer organization estimates that 31% of the households in a particular
community have one television set, 36% have two sets, and 11% have three or more
sets. What is the probability that a household chosen at random has no television sets?
- Answer- .22
,You roll a fair die 5 times. What is the probability that you roll all 4's? - Answer- 0.00013
In rolling a fair die twice, the events of getting a
3
on the first roll and a
6
on the second. - Answer- Independent
In rolling a fair die once, the events of getting a
6
and getting a
2
on that
roll - Answer- Disjoint
A survey of senior citizens at a doctor's office shows that 41% take blood pressure-
lowering medication, 41% take cholesterol-lowering medication, and 18% take both
medications. What is the probability that a senior citizen takes either blood pressure-
lowering or cholesterol-lowering medication? - Answer- 0.640
If one of the
994
subjects is randomly selected, find the probability that the person chosen is a female
nonsmoker. - Answer- .364
A box contains batteries of which
18
are defective and
12
are good. You start picking batteries one at a time and testing them. What is the
probability that the first four batteries you pick are all defective? - Answer- .112
You draw a card at random from a standard deck of 52 cards. Find the probability that
the card is a diamond given that it is a queen - Answer- .25
You draw a card at random from a standard deck of 52 cards. Find the probability that
the card is a heart given that it is black. - Answer- 0
A group of volunteers for a clinical trial consists of 70 women and 82 men. 18 of the
women and 25 of the men have high blood pressure. If one of the volunteers is selected
at random find the probability that the person is a man given that they have high blood
pressure. - Answer- .581
You are dealt a hand of three cards, one at a time. Find the probability that you have at
least one queen - Answer- .217
, If you draw a card at random from a well-shuffled deck, is getting a club independent of
getting a queen? Explain - Answer- C.
Yes. P(Club) =14 ; P(Club|Queen) =
A teacher designs a test so that 81% of students who study will pass and 9% of
students who don't study will pass. 84% of students study for a test. What is the
probability that a randomly selected student passes? - Answer- .695
Some employers use lie detector tests to screen job applicants. Lie detector tests are
not completely reliable. Suppose that a polygraph can detect 70% of lies, but incorrectly
identifies 11% of true statements as lies. A company gives its job applicants a polygraph
test, asking "Did you tell the truth on your job application?". All the applicants answer
"Yes", but the test identifies some of those answers as lies, thereby causing the person
to fail the test. Suppose that 91% of the job applicants tell the truth during the polygraph
test. What is the probability that a person who fails the test was actually telling the truth?
- Answer- .614
Question content area bottom
Part 1
x
100
200
300
400
P(X = x)
0.16
0.21
0.15
0.48 - Answer- 295
Nutritionists at a large university investigating the impact of dining hall food choices on
freshman weight gain collected data (through weekly surveys) from 300 students
throughout their freshman year. They kept track of the student's age, the number of
times eating in the hall per week, the number of hours spent exercising per week, and
the student's weight each week.
A.
Who: Nutritionists; Cases: Each student is a case; What: Student's age, number of
times eating in hall weekly, number of hours exercising weekly, and the student's
weekly weight; When: Freshman year; Where: A large university; Why: To study the
impact of dining hall choices on freshman weight gain; How: Weekly surveys.
B.
Who: 300 freshman students; Cases: Each student is a case; What: Student's age,
number of times eating in hall weekly, number of hours exercising weekly, and the
student's weekly weight; W - Answer- B.
Who: 300 freshman students; Cases: Each student is a case; What: Student's age,
number of times eating in hall weekly, number of hours exercising weekly, and the
AND ANSWERS ALL CORRECT
The plastic arrow on a spinner for a child's game stops rotating to point at a color that
will determine what happens next. Determine whether the following probability
assignment is legitimate.
Probability of . . .
Red
Yellow
Green
Blue
0.24
0.17
0.12
0.47 - Answer- Legitimate
The plastic arrow on a spinner for a child's game stops rotating to point at a color that
will determine what happens next. Determine whether the following probability
assignment is legitimate.
Probability of . . .
Red
Yellow
Green
Blue
0.25
0.21
0.17
0.47 - Answer- Not legitimate
In a survey of American women who were asked to name their favorite color, 19% said
blue, 20% said red, 12% said green, 13% said yellow, 36% said black, and the rest
named another color. If you pick a survey participant at random, what is the probability
that her favorite color is yellow or black? - Answer- .49
A consumer organization estimates that 31% of the households in a particular
community have one television set, 36% have two sets, and 11% have three or more
sets. What is the probability that a household chosen at random has no television sets?
- Answer- .22
,You roll a fair die 5 times. What is the probability that you roll all 4's? - Answer- 0.00013
In rolling a fair die twice, the events of getting a
3
on the first roll and a
6
on the second. - Answer- Independent
In rolling a fair die once, the events of getting a
6
and getting a
2
on that
roll - Answer- Disjoint
A survey of senior citizens at a doctor's office shows that 41% take blood pressure-
lowering medication, 41% take cholesterol-lowering medication, and 18% take both
medications. What is the probability that a senior citizen takes either blood pressure-
lowering or cholesterol-lowering medication? - Answer- 0.640
If one of the
994
subjects is randomly selected, find the probability that the person chosen is a female
nonsmoker. - Answer- .364
A box contains batteries of which
18
are defective and
12
are good. You start picking batteries one at a time and testing them. What is the
probability that the first four batteries you pick are all defective? - Answer- .112
You draw a card at random from a standard deck of 52 cards. Find the probability that
the card is a diamond given that it is a queen - Answer- .25
You draw a card at random from a standard deck of 52 cards. Find the probability that
the card is a heart given that it is black. - Answer- 0
A group of volunteers for a clinical trial consists of 70 women and 82 men. 18 of the
women and 25 of the men have high blood pressure. If one of the volunteers is selected
at random find the probability that the person is a man given that they have high blood
pressure. - Answer- .581
You are dealt a hand of three cards, one at a time. Find the probability that you have at
least one queen - Answer- .217
, If you draw a card at random from a well-shuffled deck, is getting a club independent of
getting a queen? Explain - Answer- C.
Yes. P(Club) =14 ; P(Club|Queen) =
A teacher designs a test so that 81% of students who study will pass and 9% of
students who don't study will pass. 84% of students study for a test. What is the
probability that a randomly selected student passes? - Answer- .695
Some employers use lie detector tests to screen job applicants. Lie detector tests are
not completely reliable. Suppose that a polygraph can detect 70% of lies, but incorrectly
identifies 11% of true statements as lies. A company gives its job applicants a polygraph
test, asking "Did you tell the truth on your job application?". All the applicants answer
"Yes", but the test identifies some of those answers as lies, thereby causing the person
to fail the test. Suppose that 91% of the job applicants tell the truth during the polygraph
test. What is the probability that a person who fails the test was actually telling the truth?
- Answer- .614
Question content area bottom
Part 1
x
100
200
300
400
P(X = x)
0.16
0.21
0.15
0.48 - Answer- 295
Nutritionists at a large university investigating the impact of dining hall food choices on
freshman weight gain collected data (through weekly surveys) from 300 students
throughout their freshman year. They kept track of the student's age, the number of
times eating in the hall per week, the number of hours spent exercising per week, and
the student's weight each week.
A.
Who: Nutritionists; Cases: Each student is a case; What: Student's age, number of
times eating in hall weekly, number of hours exercising weekly, and the student's
weekly weight; When: Freshman year; Where: A large university; Why: To study the
impact of dining hall choices on freshman weight gain; How: Weekly surveys.
B.
Who: 300 freshman students; Cases: Each student is a case; What: Student's age,
number of times eating in hall weekly, number of hours exercising weekly, and the
student's weekly weight; W - Answer- B.
Who: 300 freshman students; Cases: Each student is a case; What: Student's age,
number of times eating in hall weekly, number of hours exercising weekly, and the
