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The probable is what usually happens. Aristotle. Chapter 6: Probability. Chance experiment: any activity or situation in which there is uncertainty about which outcome will result. Fate laughs at probabilities. Bulwer, Lytton E.G.
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The probable is what usually happens. Aristotle Chapter 6: Probability
Chance experiment: any activity or situation in which there is uncertainty about which outcome will result Fate laughs at probabilities. Bulwer, Lytton E.G.
Sample Space: collection of all possible outcomes of a chance experiment Roll a die S={1,2,3,4,5,6} Probability is the very guide of life. Cicero
What is the sample space? 1.) Rolling 1 die 2.) Rolling 2 dice and counting the number of pips face up 3.) Toss a coin 4.) Toss a coin three times and record the results 5.) Flip a coin and roll a die S = {1,2,3,4,5,6} S = {2,3,4,5,6,7,8,9,10,11,12} S = {H,T} S = {HHH,HHT,HTH,THH,HTT,THT,TTH,TTT} S = {H1,H2,H3,H4,H5,H6,T1,T2,T3,T4,T5,T6}
An event is any collection of outcomes from the sample space of a chance experiment. • Rolling a prime # E = {2,3,5} • A simple event is an event consisting of exactly one outcome. Rolling a 6: E = {6}
Venn Diagrams • Used to display relationships • between events • Helpful in calculating probabilities
Consists of all outcomes that are not in the event Not rolling a even # EC={1,3,5} Complement
The rectangle represents the sample space and shaded area represents the event A. The shaded area represents the event not A.
Union • the event A or B happening • consists of all outcomes that are in at least one of the two events • Rolling a prime # or even number E={2,3,4,5,6}
Union (or) The shaded area represents the event A or B ( the union of two events).
Intersection • the event A and B happening • consists of all outcomes that are in both events • Drawing a red card and a “2” • E = {2 hearts, 2 diamonds}
Intersection (and) The shaded area represents the event A and B (the intersection of two sets).
two events have no outcomes in common Roll a “2” or a “5” Mutually Exclusive (disjoint)
Two events that have no common outcomes are said to be disjoint or mutually exclusive. A and B are disjoint events
B A B A C C A, B & C are Disjoint B A B A C C Some illustrations A ∩ B ∩ C A υ B υ C A ∩ B ∩ Cc
Stat Cal Com Sci Com Sci Statistics & Computer Science & not Calculus
Cal Stat Com Sci Calculus or Computer Science
Stat Cal Com Sci (Statistics or Computer Science) and not Calculus
Cal Stat Com Sci Statistics and not (Computer Science or Calculus)
Stat Cal 105 30 20 10 10 20 80 Com Sci Statistics or Computer Science? 170
Stat Cal 105 30 20 10 10 20 80 Com Sci 20 Statistics and Computer Science?
Stat Cal 105 30 20 10 20 10 80 Com Sci Statistics or (Computer Science and Calculus)? 90
Stat Cal 105 30 20 10 10 20 80 Com Sci (Statistics or Computer Science) and Calculus? 50
Country-Western songs emphasize three basic themes: love, prison, and trucks. A survey of the local Country-Western radio station produced the following data: 12 songs about a truck driver who is in love while in prison 2 about people in prison who are not in love and do not drive trucks 8 about people who are out of prison, are not in love, and do not drive a truck 13 about a prisoner in love 28 about a person in love 18 about a truck driver in love 16 about truck drivers who are not in prison 3 about a truck driver in prison who is not in love
12 songs about a truck driver who is in love while in prison 2 about people in prison who are not in love and do not drive trucks 8 about people who are out of prison, are not in love, and do not drive a truck 13 about a prisoner in love 28 about a person in love 18 about a truck driver in love 16 about truck drivers who are not in prison 3 about a truck driver in prison who is not in love How many songs were about: a.) truck drivers? b.) prisoners? c.) truck drivers in prison? d.) people not in prison? e.) people not in love? f.) How many songs were surveyed?
Always be a little improbable. Wilde, Oscar