Studied by 8 peopleNumber of successful outcomes/total number of possible outcomes
How to calculate P(event)
Something that can happen as a result of a trial
What’s an outcome?
The number of times you expect an event to happen
What’s the expected frequency?
P(outcome)*number of trials
How to calculate expected frequency
no. of trials with success/total no. of trials
How to calculate estimated probability
Number of trials
What increases the reliability of estimated probability?
Relative frequency
What’s another way to say estimated probability?
The probability of an event occurring for negative events
What’s the risk?
No. of trials where event happens/total no. of trials
How to calculate risk of event
How likely an event is to happen
What’s the absolute risk?
How much more likely an event is to happen for one group compared to another group
What is relative risk?
Risk for those in the group/risk for those not in the group
How to calculate relative risk
Events that cannot happen at the same time
What are mutually exclusive events?
The set contains all the possible outcomes
What does exhaustive mean?
1
In mutually exclusive and exhaustive events, what’s the sum of the probabilities?
P(A or B)=P(A)+P(B)
P(A)+P(not A)=1
P(not A)=1-P(A)
What is the addition law for ME events?
Mutually exclusive events
What doesn’t the general addition law not apply for?
P(A or B)=P(A)+P(B)-P(A and B)
What’s the general addition law?
The intersect
How is P(A and B) represented on a Venn diagram?
Everything in both circles
How is P(A or B) represented on a Venn diagram?
Unconnected events
What are independent events?
P(A and B)=P(A)*P(B)
What’s the rule for 2 independent events?
P(A and B and C)=P(A)**P(B)**P(C)
What’s the rule for 3 independent events?
When one event affects the other
What’s conditional probability?
The probability of B given that A happened
What does P(B|A) mean?
If phrases like ‘given that’ or ‘if’ are used
How can you tell if something’s conditional probability?
P(A and B)/P(B)
How to calculate P(B|A)
P(B|A)*P(A)
How to calculate P(A and B)
The events are conditional, not independent
What does if mean if P(A) isn’t equal to P(A|B)?
Note
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