##### stats 5.1-5.4

probability experiment

any process with uncertain results that can be repeated

probability

a measure of likelihood of a random phenomenon or chance behavior . it is the proportion of time a random experiment results in a particular outcome if repeated many times over a long time

the law of large numbers

as the number of repetitions of a probability experiment increases, the proportion of obtaining an outcome gets closer to probability of that outcome

sample space

the collection of all possible outcomes

unusual event

an event that has a low probability of occurring (<0.05)

conditional probability

probability of even A occurring if we know that B occurred

classical method

based on an assumption about the world where we assume that all outcomes in the sample space S are equally likely

empirical method

based on collecting sample data using statistical methods. such probabilities will differ from sample to sample

subjective method

based on personal, educated guess; even if the experiment cannot happen again

independent

if occurrence of the events does not change the probability of occurrence of the other event. it is irrelevant to the occurrence of the other