AP Statistics Practice Quiz: Introduction to Probability
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 16 questions to check your progress.
Question 1 of 16
All Questions (16)
A) The most likely outcome of the experiment.
B) The set of all possible non-overlapping outcomes of the experiment.
C) The long-run relative frequency of an event.
D) A number between 0 and 1 representing the chance of an event.
Correct Answer: B
The sample space is defined as the set of all possible non-overlapping outcomes for a random process or experiment.
A) It will rain for exactly 80% of the day tomorrow.
B) It is guaranteed to rain tomorrow.
C) In the long run, on days with similar weather conditions, it rained on about 80% of those days.
D) It will not rain tomorrow.
Correct Answer: C
Probability is best interpreted as the long-run relative frequency of an event. It describes the proportion of times an event would occur over many repetitions of the same conditions.
A) 1/6
B) 2/6
C) 4/6
D) 5/6
Correct Answer: B
The sample space is {1, 2, 3, 4, 5, 6}, with a total of 6 equally likely outcomes. The outcomes greater than 4 are {5, 6}, which is 2 outcomes. Therefore, the probability is 2/6.
A) 0.35
B) -0.35
C) 0.65
D) 1.35
Correct Answer: C
The probability of the complement of an event E is calculated as 1 - P(E). Therefore, the probability of the complement is 1 - 0.35 = 0.65.
A) 3/7
B) 3/10
C) 1/3
D) 7/10
Correct Answer: B
The total number of outcomes is the total number of marbles, which is 5 + 3 + 2 = 10. The number of outcomes in the event 'drawing a blue marble' is 3. Since all outcomes are equally likely, the probability is 3/10.
A) The event is very likely to occur.
B) The student made an error in their calculation.
C) The event is certain to occur.
D) The event is impossible.
Correct Answer: B
The probability of any event must be a number between 0 and 1, inclusive. A value of 1.15 is outside this valid range, indicating a calculation error.
A) 26/52
B) 0
C) 1/52
D) 25/52
Correct Answer: A
The event 'not red' is the complement of the event 'red'. The probability of drawing a red card is P(Red) = 26/52. The probability of the complement is 1 - P(Red) = 1 - 26/52 = 26/52. Alternatively, 'not red' means 'black', and there are 26 black cards.
A) The player will make exactly 3 out of the next 4 free throws.
B) The player will make 75 consecutive free throws and then miss the next 25.
C) If the player takes a very large number of free throws, the proportion of made shots will be close to 0.75.
D) The player is more likely to miss the next free throw than to make it.
Correct Answer: C
Probability is interpreted as the long-run relative frequency of an event. It describes a pattern over many repetitions, not a guaranteed outcome for a small number of trials.
A) Sample space size = 4; Probability = 1/2
B) Sample space size = 8; Probability = 1/4
C) Sample space size = 8; Probability = 1/2
D) Sample space size = 4; Probability = 1/4
Correct Answer: C
The sample space is the set of all possible outcomes, {1, 2, 3, 4, 5, 6, 7, 8}, so its size is 8. The even numbers are {2, 4, 6, 8}, so there are 4 favorable outcomes. The probability is 4/8 = 1/2.
A) The event of rolling a number less than 3.
B) The event of rolling a prime number.
C) The event of rolling a 6.
D) The event of rolling an even number.
Correct Answer: D
The sample space is {1, 2, 3, 4, 5, 6}. Event E (odd number) is {1, 3, 5}. The complement of E consists of all outcomes in the sample space that are not in E, which is {2, 4, 6}. This is the event of rolling an even number.
A) 0
B) 0.5
C) 1
D) It depends on the number of outcomes in the sample space.
Correct Answer: C
The probability of an event is a number between 0 and 1, inclusive. A probability of 1 indicates that the event is certain to occur.
A) 1/4
B) 1/2
C) 3/4
D) 1
Correct Answer: C
The sample space of two coin tosses is {HH, HT, TH, TT}. There are 4 equally likely outcomes. The outcomes with at least one head are {HH, HT, TH}, which is 3 outcomes. Therefore, the probability is 3/4. Alternatively, the complement is getting no heads (TT), which has a probability of 1/4. So, P(at least one head) = 1 - P(no heads) = 1 - 1/4 = 3/4.
A) Exactly 1 out of every 100 components will be defective.
B) The first 99 components will be good, and the 100th will be defective.
C) It is impossible for two consecutive components to be defective.
D) Over a very large production run, the proportion of defective components will approach 1%.
Correct Answer: D
This is the long-run relative frequency interpretation of probability. It does not guarantee the outcome for any specific small sample but describes the overall trend in a large number of trials.
A) 15/10
B) 10/25
C) 15/25
D) 1/15
Correct Answer: C
The total number of outcomes is the total number of students, which is 15 + 10 = 25. The number of outcomes in the event 'student is a freshman' is 15. Since the selection is random, all outcomes are equally likely. The probability is 15/25.
A) The number of face cards is incorrect.
B) The denominator should be the total number of outcomes in the sample space, not the number of non-favorable outcomes.
C) The outcomes are not equally likely.
D) The probability of the complement was calculated instead.
Correct Answer: B
The formula for probability with equally likely outcomes is P(E) = (number of outcomes in E) / (total number of outcomes). The student correctly identified 12 outcomes in the event but used the number of outcomes in the complement (40) as the denominator instead of the total number of outcomes in the sample space (52).
A) 3/20
B) 1/20
C) 17/20
D) 3/17
Correct Answer: C
First, find the probability of the event 'defective'. There are 3 defective bulbs out of a total of 20. So, P(defective) = 3/20. The question asks for the probability that the bulb is NOT defective, which is the complement. P(not defective) = 1 - P(defective) = 1 - 3/20 = 17/20. Alternatively, there are 20 - 3 = 17 non-defective bulbs, so the probability is 17/20.