Chapter 1 (Probability) Flashcards
Probability measures…
The likelihood of observing a particular outcome of a random process.
What is the basic formula for probability?
P(event) = # outcomes/ # of events in the sample space.
What is sample space?
Set consisting of all possible outcomes of a random process.
What is a random variable?
A random variable assigns a numeric value to each outcome of an experiment.
What is A’? (A complement)
The event consisting of all outcomes in S that are not in A.
Two events are mutually exclusive if…?
They have no outcomes in common.
What is conditional probability?
The conditional probability of A|B (“A given B”, “A conditional on B”), is the probability that event A occurs given that event B occurs. We write P(A|B).
What is a probability tree?
A diagram in which tree “branches” correspond to experimental outcomes.
What does it mean if two events are independent?
A is independent of B (or vice versa), if P(A|B) = P(A)
In other words, knowledge about B doesn’t change the probability of A.
The # of parameters is always equal to…
The # of populations.
How do you find P(A|B)?
P(AintersectB)/P(B), for P(B) GT 0 (GT = greater than)
What is the P(AintersectB)?
P(A|B) x P(B)
Or
P(B|A)xP(A)
What is P(AUB)?
P(A) + P(B) - P(AintersectB)
What is a permutation?
When you choose k objects from n total objects with order and without replacement.
The situation of
n(n-1)…(n-k+1)
What is a combination?
Choosing unordered objects without replacement!
n “choose” k
