STAT 330 - CHAPTER 2 | GUARANTEED SUCCESS STARTS
HERE! LEARN, PRACTICE & EXCEL!
Q: What is a probability experiment? Answer: A process that leads to well-defined outcomes.
Q: What is a sample space? Answer: The set of all possible outcomes of an experiment.
Q: What is an event? Answer: Any subset of the sample space.
Q: What is a simple event? Answer: An event consisting of exactly one outcome.
Q: What is the complement of an event A? Answer: All outcomes in the sample space not in A.
Q: What is the union of two events A and B? Answer: Outcomes in A, or B, or both (A ∪ B).
Q: What is the intersection of two events A and B? Answer: Outcomes that are in both A and B
(A ∩ B).
Q: What does it mean if two events are mutually exclusive? Answer: They cannot occur at the
same time (A ∩ B = ∅).
Q: What is the addition rule for probability? Answer: P(A ∪ B) = P(A) + P(B) - P(A ∩ B).
Q: What is the special addition rule for mutually exclusive events? Answer: P(A ∪ B) = P(A) +
P(B).
Q: What is conditional probability? Answer: P(A|B) = P(A ∩ B) / P(B), given P(B) > 0.
Q: What is the multiplication rule? Answer: P(A ∩ B) = P(A|B)P(B).
Q: What does it mean if two events are independent? Answer: P(A ∩ B) = P(A)P(B).
Q: What is Bayes' Rule? Answer: P(A|B) = P(B|A)P(A) / P(B).
Q: What are the three axioms of probability? Answer: "1) P(S) = 1, 2) 0 ≤ P(A) ≤ 1, 3) If A1, A2,...
are disjoint, P(A1 ∪ A2 ∪ ...) = ΣP(Ai)."
Q: What is a counting rule for ordered arrangements? Answer: Permutations: P(n,r) = n! / (n-r)!.
Q: What is a counting rule for unordered selections? Answer: Combinations: C(n,r) = n! / (r!(n-
r)!).
Q: Example: How many ways to pick 3 people from 10 for a committee? Answer: C(10,3) = 120.
Q: Example: How many ways to arrange 3 books out of 5 on a shelf? Answer: P(5,3) = 60.
Q: What is the probability of the empty set? Answer: P(∅) = 0.
APPHIA – Crafted with Care and Precision for Academic Excellence.
1
HERE! LEARN, PRACTICE & EXCEL!
Q: What is a probability experiment? Answer: A process that leads to well-defined outcomes.
Q: What is a sample space? Answer: The set of all possible outcomes of an experiment.
Q: What is an event? Answer: Any subset of the sample space.
Q: What is a simple event? Answer: An event consisting of exactly one outcome.
Q: What is the complement of an event A? Answer: All outcomes in the sample space not in A.
Q: What is the union of two events A and B? Answer: Outcomes in A, or B, or both (A ∪ B).
Q: What is the intersection of two events A and B? Answer: Outcomes that are in both A and B
(A ∩ B).
Q: What does it mean if two events are mutually exclusive? Answer: They cannot occur at the
same time (A ∩ B = ∅).
Q: What is the addition rule for probability? Answer: P(A ∪ B) = P(A) + P(B) - P(A ∩ B).
Q: What is the special addition rule for mutually exclusive events? Answer: P(A ∪ B) = P(A) +
P(B).
Q: What is conditional probability? Answer: P(A|B) = P(A ∩ B) / P(B), given P(B) > 0.
Q: What is the multiplication rule? Answer: P(A ∩ B) = P(A|B)P(B).
Q: What does it mean if two events are independent? Answer: P(A ∩ B) = P(A)P(B).
Q: What is Bayes' Rule? Answer: P(A|B) = P(B|A)P(A) / P(B).
Q: What are the three axioms of probability? Answer: "1) P(S) = 1, 2) 0 ≤ P(A) ≤ 1, 3) If A1, A2,...
are disjoint, P(A1 ∪ A2 ∪ ...) = ΣP(Ai)."
Q: What is a counting rule for ordered arrangements? Answer: Permutations: P(n,r) = n! / (n-r)!.
Q: What is a counting rule for unordered selections? Answer: Combinations: C(n,r) = n! / (r!(n-
r)!).
Q: Example: How many ways to pick 3 people from 10 for a committee? Answer: C(10,3) = 120.
Q: Example: How many ways to arrange 3 books out of 5 on a shelf? Answer: P(5,3) = 60.
Q: What is the probability of the empty set? Answer: P(∅) = 0.
APPHIA – Crafted with Care and Precision for Academic Excellence.
1
