Q: In a survey, 1782 out of 2002 adults said they use the Internet. What is the probability that a randomly selected adult does NOT use the Internet?

$$P(\text{not using Internet}) = \frac{220}{2002} \approx 0.110$$

Q: In a survey, 366 out of 2003 adults said they have seen a ghost. What is the probability that a randomly selected adult has NOT seen a ghost?

$$P(\text{not seen}) = \frac{1637}{2003} \approx 0.817$$

Question 1

Which of the following best describes a simple event in probability?

Accepted Answer

An outcome that cannot be further broken down into simpler components.

Question 2

A die is rolled once. What is the probability of rolling a 5 using the classical approach?

Accepted Answer

$$P(5) = \frac{1}{6}$$

Question 3

In a survey, 1782 out of 2002 adults said they use the Internet. What is the probability that a randomly selected adult does NOT use the Internet?

Accepted Answer

$$P(	ext{not using Internet}) = \frac{220}{2002} \approx 0.110$$

Question 4

Which of the following is NOT a valid approach to finding probability?

Accepted Answer

Experimental approach with unequal likelihoods (without adjustment)

Question 5

If the probability of an event is 0.001, how would you interpret this probability?

Accepted Answer

The event is very unlikely to occur.

Question 6

A roulette wheel has 38 slots. If you bet on the number 13, what are the actual odds against winning?

Accepted Answer

37:1

Question 7

Which statement best describes the Law of Large Numbers?

Accepted Answer

As the number of trials increases, the relative frequency probability approaches the actual probability.

Question 8

In a simulation, which of the following is true?

Accepted Answer

A simulation mimics the behavior of a real procedure to estimate probabilities.

Question 9

If the probability of an event A is $$P(A) = 0.2$$, what is the probability of the complement of A?

Accepted Answer

$$P(A^c) = 0.8$$

Question 10

A casino offers payoff odds of 35:1 for a $5 bet on a single number in roulette. If you win, what is your net profit?

Accepted Answer

$$175$$

Question 11

Which of the following best describes a sample space?

Accepted Answer

A collection of all possible simple events for a procedure.

Question 12

In a survey, 366 out of 2003 adults said they have seen a ghost. What is the probability that a randomly selected adult has NOT seen a ghost?

Accepted Answer

$$P(	ext{not seen}) = \frac{1637}{2003} \approx 0.817$$

Question 13

Which of the following is an example of a subjective probability?

Accepted Answer

Estimating the chance of rain tomorrow based on weather patterns.

Question 14

If the probability of an event is 0.04, according to the rare event rule, what can you conclude if the event occurs?

Accepted Answer

The assumption about the probability may not be correct.

Question 15

Which of the following is true about odds in favor and odds against an event?

Accepted Answer

If the odds against an event are a:b, the odds in favor are b:a.

Question 16

A medical test has a 0.98 probability of correctly identifying a disease when it is present. What is the probability that the test fails to identify the disease when it is present?

Accepted Answer

$$P(	ext{fail}) = 0.02$$

Question 17

If a procedure has 8 equally likely simple events and event A can occur in 3 ways, what is $$P(A)$$ using the classical approach?

Accepted Answer

$$P(A) = \frac{3}{8}$$

Question 18

Which of the following is a correct interpretation of the Law of Large Numbers in the context of flipping a fair coin?

Accepted Answer

As the number of flips increases, the proportion of heads will get closer to 0.5.

Question 19

A casino offers payoff odds of 35:1, but the actual odds against winning are 37:1. What does this imply about the casino's profit?

Accepted Answer

The casino makes a profit because the payoff odds are less favorable than the actual odds.

Chapter 4: Probability – Structured Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드