Q: Which of the following is a correct application of the complement rule?

If $$P(A) = 0.7$$, then $$P(\text{not } A) = 0.3$$

Question 1

Which of the following best describes a statistical random experiment?

Accepted Answer

Any random activity that results in a definite outcome.

Question 2

If you roll a standard six-sided die, what is the probability of rolling a number greater than 4?

Accepted Answer

$$\frac{2}{6}$$

Question 3

A random sample of 400 students at a college were surveyed, and 300 of them liked the food in the cafeteria. What is the empirical probability that a randomly selected student likes the cafeteria food?

Accepted Answer

$$\frac{3}{4}$$

Question 4

Which of the following is an example of a simple event?

Accepted Answer

Rolling a die and getting a 3.

Question 5

What is the complement of the event 'getting at least one head' when tossing two fair coins?

Accepted Answer

Getting no heads.

Question 6

A sports announcer claims that Sheila has a 90% chance of breaking the record in the 100-yard dash. What type of probability assignment is this?

Accepted Answer

Subjective (intuition/educated guess)

Question 7

If the probability that a student has not received a flu shot is 0.65, what is the probability that a student has received a flu shot?

Accepted Answer

$$0.35$$

Question 8

Which of the following statements about the Law of Large Numbers is correct?

Accepted Answer

As the sample size increases, the relative frequency of an event gets closer to the theoretical probability.

Question 9

You are guessing a four-digit PIN number, where each digit can be any number from 0 to 9. What is the total number of possible outcomes in the sample space?

Accepted Answer

$$10^4$$

Question 10

Which of the following is NOT a valid probability value?

Accepted Answer

$$-0.2$$

Question 11

A frequency table shows that 8 students are aged 18-25, 12 are aged 26-32, and 10 are aged 33-39. What is the probability that a randomly chosen student is aged 26-32?

Accepted Answer

$$\frac{12}{30}$$

Question 12

Which of the following best describes a simulation in probability?

Accepted Answer

A procedure that uses a computer or random device to mimic a real-world process.

Question 13

If the probability of event $$A is$$ $$0.3$$ and the probability of event $$B is$$ $$0.5$$, and $$A$$ and $$B$$ are mutually exclusive, what is the probability that either $$A or$$ $$B$$ occurs?

Accepted Answer

$$0.8$$

Question 14

Which of the following is an example of using classical probability?

Accepted Answer

Calculating the probability of drawing an ace from a standard deck of cards.

Question 15

A random sample of 200 laboratory reports found 80 erroneous reports. What is the empirical probability of a report being erroneous?

Accepted Answer

$$0.4$$

Question 16

If you toss two fair coins, what is the probability of getting at least one head?

Accepted Answer

$$\frac{3}{4}$$

Question 17

Which of the following is a correct application of the complement rule?

Accepted Answer

If $$P(A) = 0.7$$, then $$P(	ext{not } A) = 0.3$$

Basic Concepts of Probability (Section 4.1) – Introductory Statistics Study Notes

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