Complements and expected frequency
Pages
Probabilities that sum to one
Why an exhaustive set’s probabilities total one, and checking a stated table.
The probability of an event not happening
P(not A) as 1 − P(A), and spotting when the complement is the faster route.
Finding a missing probability
Using the total of one to find an unknown probability, even an algebraic one.
Expected frequency
Estimating how many times an event will occur as probability times trials.
Expected frequency as an estimate
Why 60 rolls need not give ten sixes, and what the expected count does say.
Practice
Practice
Probabilities that sum to one
Why an exhaustive set’s probabilities total one, and checking a stated table.
PracticeThe probability of an event not happening
P(not A) as 1 − P(A), and spotting when the complement is the faster route.
PracticeFinding a missing probability
Using the total of one to find an unknown probability, even an algebraic one.
PracticeExpected frequency
Estimating how many times an event will occur as probability times trials.
PracticeSingle events review
Probability scale, the not-rule and expected frequency.