Basic Probability Concepts
Sample space is all the possible outcomes for an event.
A) True
B) False
A) True
In a class of 30 students, 20 students passed their math exam and 15 students passed their science exam. If 10 students passed both exams, what is the probability that a randomly selected student who passed the math exam also passed the science exam?
A) 0.33
B) 0.50
C) 0.60
D) 0.75
B) 0.50
A jar contains 5 purple marbles, 10 blue marbles, and 6 white marbles. Two marbles are randomly selected, without replacement. What is the probability of not getting a white marble?
A) 6/21
B) 5/21
C) 16/21
D) 15/21
C) 16/21
A fair coin is to be flipped 5 times. The first 4 flips land 'heads up.' What is the probability of 'heads' on the next (5th) flip of this coin?
A) 1
B) ½
C) (5)(½)^4(½)
D) (½)^4(½)
E) 0
B) 1/2
Two events are mutually exclusive if they cannot occur simultaneously
A) False
B) True
B) True
A set of all possible outcomes is known as...
A) a list
B) a complement
C) a sample space
D) an event
C) a sample space
A recent survey suggests that 85% of college students have posted a profile on Facebook, 73% use YouTube regularly, and 66% do both. What is the probability that a randomly selected student uses YouTube regularly given that they have a Facebook profile?
A) 0.776
B) 0.904
C) 0.859
D) 0.824
A) 0.776
A high school science club has 40 students, of whom 6 are right-handed. Two students from the club will be selected at random, one at a time without replacement. What is the probability that the 2 students selected will both be right-handed?
A) 30/1600
B) 30/1560
C) 6/40
D) 1156/1600
B) 30/1560
A fair six-sided die is rolled twice. What is the probability of rolling a 3 on the first roll and a 4 on the second roll?
A) 1/36
B) 1/18
C) 1/12
D) 1/6
A) 1/36
Given the probabilities P(A) = 0.4 and P(A ∪ B) = 0.6, what is the probability P(B) if A and B are mutually exclusive?"
A) 0.4
B) 0.2
C) 0.33
D) 0.6
B) 0.2
All probabilities add up to…
A) 1.25
B) 0.99
C) 0.50
D) 1
D) 1
Suppose that 85% of students who take the AP Statistics exam pass. Suppose further that 65% of those that pass receive college credit, and 4% of those that don't pass receive college credit. If a student who is chosen at random from among those taking the exam receives college credit, what is the probability that she passed the exam?
A) 0.5525
B) 0.9893
C) 0.006
D) 0.5585
B) 0.9893
Five juniors and four seniors have applied for two open student council positions, and administrators have decided to pick two new members randomly. What is the probability that they are both from the same grade?
A) 0.395
B) 0.444
C) 0.506
D) 0.569
A) 0.395
A deck of cards contains 52 cards. One card is drawn, replaced, and then another card is drawn. What is the probability that both cards drawn are queens?
A) 1/221
B) 1/52
C) 4/52
D) 1/26
B) 1/52
In a class of 30 students, 18 are female and 12 are male. If a student is selected at random, what is the probability that the student is male or a female?
A) 0.3
B) 0.4
C) 0.5
D) 0.6
C) 0.5
Law of large numbers states if we do something many many times, the proportion of desired outcomes will approach its probability.
A) True
B) False
A) True
A certain medical test is 95% effective in detecting a disease when it is present, but also gives a false positive 2% of the time when the disease is not present. If 1% of the population has the disease, what is the probability that a person who tests positive actually has the disease?
A) 0.324
B) 0.333
C) 0.337
D) 0.341
A) 0.324
A deck of cards contains 52 cards. Two cards are randomly selected, without replacement. What is the probability that both cards are aces?
A) 4/52
B) 1/221
C) 1/26
D) 1/52
B) 1/221
The probability of a car stopping at a red light is 0.7. What is the probability that a car stops at the first red light but not at the second red light if the lights are independent?"
A) 50%
B) Less than 50%, since tails is happening so much.
C) Greater than 50%, it's due to happen.
D) Can't be determined
C) Greater than 50%, it's due to happen
The weather forecast says there is a 30% chance of rain on Saturday and a 20% chance of rain on Sunday. What is the probability that it will rain on both days?"
A) 0.04
B) 0.06
C) 0.10
D) 0.60
A) 0.04
A jar contains 3 red marbles and 7 blue marbles. What is the probability of drawing a red marble?
A) 0.3
B) 0.7
C) 0.5
D) 0.1
A) 0.3
In a population, 40% have blood type A, 30% have blood type B, 20% have blood type AB, and 10% have blood type O. If a person is randomly selected, what is the probability that they have blood type A or B?
A) 0.4
B) 0.7
C) 0.6
D) 0.5
B) 0.7
A box contains 3 red balls, 4 green balls, and 5 blue balls. Two balls are randomly selected without replacement. What is the probability that both balls are green?
A) 2/11
B) 2/33
C) 1/11
D) 1/5
B) 2/33
Two spinners each have numbers 1 to 5. What is the probability that both spinners land on 5?"
A) 1/25
B) 1/10
C) 1/5
D) 1/20
A) 1/25
In a parking lot, 40% of the cars are blue, 30% are red, and 30% are white. If a person is randomly selected, what is the probability that they are driving a blue or red car?
A) 0.5
B) 0.6
C) 0.7
D) 0.4
C) 0.7