IB Math SL: Probability Exam Questions
with Correct Answers
1. Sum of all probabilities correct answer: 1
2. P(at least one) correct answer: 1 - P(none)
3. P(A|B) correct answer: P(AnB) / P(B)
4. P(B|A) correct answer: A(AnB) / P(A)
5. P(AnB) correct answer: P(A) * P(B|A)
6. P(AnB), A and B are independent correct answer: P(A) * P(B)
7. P(AuB) correct answer: P(A) + P(B) - P(AnB)
8. P(AuB), A and B are mutually exclusive correct answer: P(A) + P(B)
9. Testing for mutual exclusivity correct answer: Calculate P(AuB)
10. Testing for independence correct answer: P(AnB) = P(A) * P(B)
11. Methods for finding probabilities correct answer: Logic; two-way tables; venn
diagrams; tree diagrams; totals
table; formulae
12. probability distributions definition correct answer: function that assigns a
probability to each outcome
13. nature of discrete random variable correct answer: a random variable X can
assume a value for every outcome
in a sample space; X is discrete if all outcomes can be put in a list of separate items
14. difference between data and variable correct answer: data reflects what
underlying data did; variable repre- sents what it can do; also reflected in ditterence between data-
based relative frequency and the unchanging, theoretical probability of an event from probability
distribution
15. E(x) of discrete distribution correct answer: sum of every x multiplied by probability of
its occurence
16. Determining whether a game of chance is fair correct answer:
E(payout)=0
17. Binomial distribution definition correct answer: X~B(n,p) where there are n
independent trials and p constant
probability of success
1/
3
with Correct Answers
1. Sum of all probabilities correct answer: 1
2. P(at least one) correct answer: 1 - P(none)
3. P(A|B) correct answer: P(AnB) / P(B)
4. P(B|A) correct answer: A(AnB) / P(A)
5. P(AnB) correct answer: P(A) * P(B|A)
6. P(AnB), A and B are independent correct answer: P(A) * P(B)
7. P(AuB) correct answer: P(A) + P(B) - P(AnB)
8. P(AuB), A and B are mutually exclusive correct answer: P(A) + P(B)
9. Testing for mutual exclusivity correct answer: Calculate P(AuB)
10. Testing for independence correct answer: P(AnB) = P(A) * P(B)
11. Methods for finding probabilities correct answer: Logic; two-way tables; venn
diagrams; tree diagrams; totals
table; formulae
12. probability distributions definition correct answer: function that assigns a
probability to each outcome
13. nature of discrete random variable correct answer: a random variable X can
assume a value for every outcome
in a sample space; X is discrete if all outcomes can be put in a list of separate items
14. difference between data and variable correct answer: data reflects what
underlying data did; variable repre- sents what it can do; also reflected in ditterence between data-
based relative frequency and the unchanging, theoretical probability of an event from probability
distribution
15. E(x) of discrete distribution correct answer: sum of every x multiplied by probability of
its occurence
16. Determining whether a game of chance is fair correct answer:
E(payout)=0
17. Binomial distribution definition correct answer: X~B(n,p) where there are n
independent trials and p constant
probability of success
1/
3
