Cheatography

# AP Stat03 Anticipating Patterns Cheat Sheet (DRAFT) by taotao

This is a draft cheat sheet. It is a work in progress and is not finished yet.

### Probab­ility

 probab­ility a measure of the likelihood of an event experiment any process resulting an observ­ation or outcome sample space a set of all possible outcomes of an experiment tree diagram vs cross table vs venn diagram probab­ility rules PA [0,1] sum(PA)=1 odds in favor of an event: P(A):P(A') comple­ment: PA = 1-PA' union: P(A)+P­(B)­+P(AB) intersect: P(A)P(B|A)­=P(B)P(A|B) condit­ional event: P(A|B)­=P(­AB)­/P(B) indepe­ndent: P(AB)=­P(A­)*P(B), P(A)=P­(A|B), P(B)=P­(B|A) disjoi­n/e­xcl­usive: interrsect is 0
exampl­e:s­hopper items vs gender
autoin­sur­ance: collision protection vs involved in accident

### random variables and their prob distri­bution

 variable a quantity whose value varies from subject to subject probab­ility experi­ement an experiment with possible outcomes maybe known, but exact outcome is a random event, no certainty could be predict in advance random variable outcome of a probab­ility experiment is numeric discrete random variable quanti­tative variable that takes a countable number of values could you have half unit of your variable? No continuous random variable quanti­tative variable that can take all the possible values in a given range could you have half unit of your variable? Yes

### discrete random variable distri­bution

 Probab­ility distri­bution of discrete random variables table{ X,p(xi) } P(xi) [0,1] sum(P(­xi)=1 Mean/e­xpected value E(X)=s­um(­xi*­P(xi)) variance sum((x­i-mean)2*P(xi) ) standard deviation expected values for how much any given data point will vary from the mean