chapter 14 Flashcards
- Which of the following chances can be quantified exactly?
a. The chance that it will rain tomorrow.
b. The chance that you will live to be 100.
c. The chance of getting four of a kind in a poker hand.
d. All of the above.
C
- Which of the following is not an example of using the relative-frequency interpretation of probability?
a. Buying a lottery ticket every week and observing whether it is a winner.
b. Testing individuals in a population and observing whether they carry a gene for a certain disease.
c. Being a member of a jury and deciding that the chance of the defendant being innocent is very small.
d. All of the above are examples of using the relative-frequency interpretation.
C
- Which of the following does not apply to the relative-frequency approach for trying to determine a probability of a specific outcome?
a. The probability is determined to be the proportion of times the outcome occurs in the long run.
b. The relative frequency jumps around if only a few observations are made, but eventually settles down to a certain proportion as more and more observations are made.
c. The relative frequency approach to determining a probability can be applied to short-term observation.
d. All of the above statements apply to the relative-frequency approach.
C
- Suppose you encounter one traffic light on your commute to work each day. You have determined that the probability that this light will be red is 1/3. Which of the following is not a correct interpretation of this probability?
a. The light will always be red one out of every three times that you encounter it.
b. In the long run, the light should be red about 33.33% of the time.
c. Each time you approach the light on your commute, the probability of it being red is 1/3.
d. All of the above are correct interpretations.
A
- Suppose you know that for each ticket the probability of winning a certain “instant win” lottery game is 1/100. You have purchased 99 tickets so far, with no luck. What is your chance that the next ticket you buy is a winner?
a. 99/100
b. 1/100
c. 100%
d. None of the above.
B
- Which of the following is an example of using the personal probability interpretation of probability?
a. Buying a lottery ticket every week and observing whether it is a winner.
b. Observing the percentage of time that all of the prices ring up correctly when you visit a certain store each week to do your shopping.
c. Deciding that your football team has a high chance of winning their next game.
d. All of the above are examples of using the personal probability interpretation.
C
- Which of the following statements is not true regarding personal probabilities?
a. They often take relative frequencies of similar events into account.
b. They are based on unique situations that are not likely to be repeated.
c. We could each assign a different personal probability to the same event.
d. All of the above are true statements regarding personal probabilities.
D
- Which of the following is not an example of a statement based on a personal probability?
a. “Based on his credentials and experience, I believe this candidate has a high chance of being successful here.”
b. “I read in a study that 98% of the patients who received this vaccine suffered no side effects, so my chances of developing side effects are very small.”
c. “We believe beyond a reasonable doubt that the defendant is guilty.”
d. All of the above are statements based on personal probability.
B
- Which of the following is a true probability?
a. –0.22
b. 120%
c. 1
d. None of the above
C
- Which of the following outcomes are not mutually exclusive?
a. Flip a fair coin once. Outcomes: head, tail.
b. Flip a fair coin twice. Outcomes: getting at least one tail, getting at least one head.
c. Flip a fair coin twice. Outcomes: getting two tails, getting two heads.
d. All of the above pairs of outcomes are mutually exclusive.
B
- Suppose the outcomes of births within a given family are independent of each other, and a couple has already had four boys. Which of the following best describes the probability that their next baby will be a girl?
a. Approximately 50%
b. Much less than 50%
c. Much greater than 50%
d. Not enough information to tell
A
- Suppose your commute to work involves encountering 3 intersections in town and then getting on the Interstate for 10 miles. Your driving experiences in town and on the Interstate are unrelated. Suppose your chances of hitting a red light in town are 1 in 10, and your chances of getting tied up in traffic on the Interstate are 2 in 10. What are the chances of having both happen on the same trip to work?
a. 3/10 = .30 or 30%
b. 2/100 = .02 or 2%
c. 3/20 = .15 or 15%
d. None of the above
B
- Which of the following is an example of a cumulative probability?
a. The chance of being infected with a sexually transmitted disease by the 10th independent encounter.
b. The chance of first becoming infected with a sexually transmitted disease during the 10th encounter.
c. The total percentage of encounters resulting in the spread of a sexually transmitted disease.
d. All of the above.
A
- Which probability is the smallest?
a. The probability that a couple’s third child is a girl.
b. The probability that a couple has their first girl by the time of the third child.
c. The probability that a couple’s first girl occurs the third time around.
d. All of the above probabilities are equal.
C
- Which of the following describes an example of an expected value in a lottery situation?
a. The average amount of money you’ll win/lose in the long run when playing the lottery.
b. The amount of money you will win/lose on any given ticket.
c. The amount of money that you’ll have the highest chances of winning.
d. All of the above.
A
