Question 1

A hospital is tracking the probability that a randomly selected patient will test positive for a rare disease. Out of 1,000 patients tested, 8 test positive. Using the relative frequency approximation, what is the estimated probability that a randomly selected patient will test positive?

Accepted Answer

$$\frac{8}{1000}$$

Question 2

A fair six-sided die is rolled. What is the probability of rolling a number greater than 4 using the classical approach?

Accepted Answer

$$\frac{1}{3}$$

Question 3

Which of the following statements about probability is TRUE?

Accepted Answer

A probability of 0.5 means the event is equally likely to occur or not occur.

Question 4

If the probability of event A occurring is $$0.3$$, what is the probability of the complement of A, $$P(A')$$?

Accepted Answer

$$0.7$$

Question 5

A weather forecaster estimates a 70% chance of rain tomorrow based on her experience and current weather patterns. Which approach to probability is she using?

Accepted Answer

Subjective probability

Question 6

A bag contains 5 red, 3 blue, and 2 green marbles. If one marble is drawn at random, what is the probability that it is blue?

Accepted Answer

$$\frac{3}{10}$$

Question 7

Which of the following best describes the Law of Large Numbers?

Accepted Answer

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

Question 8

If the odds against an event A occurring are 3:7, what is the probability of event A occurring?

Accepted Answer

$$\frac{7}{10}$$

Question 9

A quality control engineer inspects 200 light bulbs and finds 4 defective ones. What is the relative frequency probability that a randomly selected bulb is defective?

Accepted Answer

$$\frac{4}{200}$$

Question 10

Which of the following is NOT a property of probability?

Accepted Answer

The probability of any event is always greater than 1.

Question 11

A lottery has 100 tickets, only one of which is a winner. What are the actual odds in favor of winning?

Accepted Answer

1:99

Question 12

If the probability of event B is $$0.04$$, is event B considered significantly low, significantly high, or neither, according to the definition of significant events?

Accepted Answer

Significantly low

Question 13

A deck of cards has 52 cards. What is the probability of drawing an ace or a king in a single draw?

Accepted Answer

$$\frac{8}{52}$$

Question 14

If the probability of event C is $$0.85$$, what are the actual odds against event C occurring?

Accepted Answer

$$\frac{0.15}{0.85}$$

Question 15

A medical test for a disease has a 98% chance of correctly identifying a diseased patient. If 1,000 patients with the disease are tested, about how many would you expect to be correctly identified, according to the Law of Large Numbers?

Accepted Answer

980

Question 16

A coin is flipped 10 times and lands heads 8 times. What is the relative frequency probability of getting heads?

Accepted Answer

$$\frac{8}{10}$$

Question 17

If the odds in favor of an event are 5:3, what is the probability of the event?

Accepted Answer

$$\frac{5}{8}$$

Question 18

A student claims that the probability of getting a 7 when rolling a standard six-sided die is $$\frac{1}{6}. $$What is wrong with this statement?

Accepted Answer

7 is not a possible outcome on a six-sided die, so the probability is 0.

Question 19

A game show contestant has a 1 in 4 chance of winning a car. What are the actual odds against winning the car?

Accepted Answer

3:1

Question 20

A researcher claims that the probability of a certain event is 1.2. What is wrong with this claim?

Accepted Answer

Probabilities must be between 0 and 1, inclusive.

Probability: Basic Concepts and Approaches

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