AP Statistics Unit 4: Probability Test
With Complete Solutions | Verified
Probability CORRECT ANSWERS How likely an event is to occur, the long run relative
frequency of an event. Cannot predict specific outcome for a random event, only what is
going to happen in the long run. Notation: P( ). Written as a decimal
And, Or, Not CORRECT ANSWERS And: P(AnB)=P(A)xP(B), must be independent
(multiplication rule)
Or: P(AUB)=P(A)+P(B), must be disjointed
Not: 1-P(A)
Independence CORRECT ANSWERS Outcome of one trial does not influence the
outcome of another. To assume independence, sample must be random. P(A/B)=P(A)
Law of Large Numbers CORRECT ANSWERS Long run relative frequencies of
repeated independent events settle down to the true probability as the number of trials
increases.
Law of Averages CORRECT ANSWERS An outcome is due to happen if it has not
happened in a while. Is false, because each event is independent.
Sample Space CORRECT ANSWERS Set of all possible outcomes. Sum of sample
space is 1
Complement CORRECT ANSWERS Probability that the event does not occur.
Complement Rule: Probability of an event is 1-complement (probability that event does
not occur).
"At least one" CORRECT ANSWERS Find probability of event not occurring and do 1-
P(not happening).
Outcome CORRECT ANSWERS Result of a trial, which is measured, observed, or
reported (ex. color of M&M pulled out of bag)
Event CORRECT ANSWERS Collection of outcomes. Have probabilities attached to
them. (ex. pulling out 3 green M&Ms)
Disjoint/Mutually exclusive CORRECT ANSWERS Two events do not share outcomes.
Therefore, if A occurs, B cannot occur. (ex. playing card cannot be hearts and spades,
so they are disjoint)
Something has to happen rule CORRECT ANSWERS Sum of all probabilities of all
possible outcomes is 1
With Complete Solutions | Verified
Probability CORRECT ANSWERS How likely an event is to occur, the long run relative
frequency of an event. Cannot predict specific outcome for a random event, only what is
going to happen in the long run. Notation: P( ). Written as a decimal
And, Or, Not CORRECT ANSWERS And: P(AnB)=P(A)xP(B), must be independent
(multiplication rule)
Or: P(AUB)=P(A)+P(B), must be disjointed
Not: 1-P(A)
Independence CORRECT ANSWERS Outcome of one trial does not influence the
outcome of another. To assume independence, sample must be random. P(A/B)=P(A)
Law of Large Numbers CORRECT ANSWERS Long run relative frequencies of
repeated independent events settle down to the true probability as the number of trials
increases.
Law of Averages CORRECT ANSWERS An outcome is due to happen if it has not
happened in a while. Is false, because each event is independent.
Sample Space CORRECT ANSWERS Set of all possible outcomes. Sum of sample
space is 1
Complement CORRECT ANSWERS Probability that the event does not occur.
Complement Rule: Probability of an event is 1-complement (probability that event does
not occur).
"At least one" CORRECT ANSWERS Find probability of event not occurring and do 1-
P(not happening).
Outcome CORRECT ANSWERS Result of a trial, which is measured, observed, or
reported (ex. color of M&M pulled out of bag)
Event CORRECT ANSWERS Collection of outcomes. Have probabilities attached to
them. (ex. pulling out 3 green M&Ms)
Disjoint/Mutually exclusive CORRECT ANSWERS Two events do not share outcomes.
Therefore, if A occurs, B cannot occur. (ex. playing card cannot be hearts and spades,
so they are disjoint)
Something has to happen rule CORRECT ANSWERS Sum of all probabilities of all
possible outcomes is 1
