Probability Flashcards
What units should you never use when dealing with probabilities?
Percentages
What is an experiment?
A repeatable process that gives rise to a number of outcomes
What is an event?
A collection of outcomes
What is a sample space?
A set of possible outcomes
What do ‘n’ and ‘u’ mean in reference to Venn Diagrams?
n - intersection (point where 2 rings overlap)
u - union (All data within rings including overlap)
What do A’, n(A) and p(A) mean?
A’ - All data points excluding A
n(A) - The number of outcomes in the event A
p(A) - The probability that event A occurs
What are independent events?
Events for which one event has no effect on the other
What are mutually exclusive events?
Events which have no outcomes in common
(events which cannot occur at the same time)
What is the formula for independent events?
P(A n B) = P(A) x P(B) as the outcome of each does not change due to the other
What is the formula for mutually exclusive events?
P(A n B) = 0 (cannot occur at the same time)
and
P(A u B) = P(A) + P(B) (No ring overlap so separate venn diagrams)
When should you use tree diagrams?
To show the probability of two or more outcomes happening in succession
What is conditional probability?
A situation in which the outcome of one event can change the probability of another occurring.
What is meant by P(B|A)?
The probability of B occurring given A has already occurred
What is the multiplication formula for conditional probability?
P(B|A) x P(A) = P(A n B)
What can be said of independent events by using conditional probability?
P(A|B) = P(A|B’) = P(A)
They all refer to the probability of A occurring as B cannot occur at the same time as A
