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Stack #59279
| Question | Answer |
|---|---|
| a phenomenon is random if | individual uotcomes are uncertain but there is nonetheless a regular distribition of outcomes in a large number of repetitions |
| the probability of any outcome of a random phenomenon is | the proportion of times the outcome would occur in a very long series of repetitions |
| multiple counting principle | if a choice consists of two steps of which the first can be made in m ways and for each of these the second can be made in n ways, then the whole choice can be made in mn ways |
| sample space | the set of all possible outcomes of a random experiment |
| elemtn | each individual outcome in the sample space |
| event | a subset of the sample space |
| relative frequencies are often used | to estimate probability |
| mutually exclusive events | two events that have no element in common |
| a union b | is the set of elemnts which belong to set a OR b or both |
| a intersect b | is the set of elements which belong to set a AND b |
| A' is | teh set of elemnts that are NOT in set a but are in the sample space |
| the probability p(a) of any event is always | a number between 0 and 1 inclusive. |
| an event with the probability 0 is | impossible |
| event with a probaility 1 is | certain |
| if s is the sample space | then p(s)=1 |
| complement rule | P(A')= 1-p(a) |
| addition rule for mutaully exclude events | if a and b are disjoint events then P(AUB)=(PA)+P(B) |
| two events are independt if | knowing that one occurs does not change the probality that the other occurs |
| if A and B are independent events then P (A and B)= | P(A) P(B) |
| general addition rule for porbability | P (AUB)=P(A)+P(B)-P (AnB) |