Download Unit 4 Summary : Probability (Part 1)

Unit 4 Summary : Probability (Part 1)
Things to know:
1. Simple Probabilities; P(rolling even on a die) = 1/2
2. Cardinality notation; n(A) --> number of elements in A
3. A' means not A; If event A means rolling a 2, then event A' would
be the event of rolling a 1, 3, 4, 5, or 6.
4. P(A|B) means the probability of event A given event B.
5. How to modify a sample space to an altered sample space for
conditional probability: P(rolling 3 | rolling odd) --> the sample
space was originally {1, 2, 3, 4, 5, 6} but the alterned sample space
is {1, 3, 5}.
6. How to use tree diagrams to solve probabilities.
7. How to use the "And" formula to solve a pair of sequential events.
Ex: P(drawing two Aces) = P(ace second card n ace first card)
8. Mutually Exclusive Events - both events cannot happen
simultaneously.
9. Independent Events - the outcome of event A does not change the
probability of event B occurring.
10.Be able to use the complement; P(A) = 1 - P(A').
Ex; P(rolling a 2, 3, 4, 5, or 6) = 1 - P(rolling a 1)
The test will not have the following:
Milton Bradley like questions -->ie; P(hitting 2/5 at bats).
Formulas to Memorize
Additive Principle
P( A  B)  P( A)  P( B)  P( A  B)
P( A  B)  P( A)  P( B)
(if events are mutually exclusive)
"And" Formula
P( A  B)  P( A | B)  P( B)
P( A  B)  P( A)  P( B)
"Given" Formula
P( A | B) 
P( A  B)
P( B)
(if events are independent)