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Flashcards in Theory Deck (13)
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1

What is the probability that event A occurs?

P(A)

2

What is the probability that A OR B happens?

P(A) + P(B), P(A+B), P(AUB)

3

What is the probability that event A AND B occur?

P(A*B), P(AB), P(A∩B)

4

What does mutually exclusive events mean?

That A and B cannot occur at the same time. E.g. Male is pregnant.
P(A∩B) = 0

5

What does independent events mean?

Occurrence of A does not affect the occurrence of B. First patient is male, second patient is a woman.

6

What does conditional probability mean?

Probability of A given that B has occurred. P(AIB)
E.g. probability that a patient has a headache when having fever

7

What is the risk of illness if risk factor is present?

a / a+b

Having disease with risk factor / having disease and not having disease with risk factor

8

Risk of having illness when no risk factor is resent

c / c+d

Having disease without risk factor/ having disease and not having disease without risk factor

9

What is the risk ratio/ relative risk?

Risk ratio is the probability of an event occurring if a risk factor is present to the probability of an event occurring if a risk factor is not present.

a*(c+d) / c*(a+b)

10

What does odds mean?

Odds is how many times the probability of an event occurring is greater than not occurring.

O = P(A) / 1 - P(A)

11

What is the odds of having an illness if the risk factor is present?

a/b

12

What is the odds of having an illness if the risk factor is not present?

c/d

13

What is odds ratio?

The ratio of the odds of an event occurring if a risk factor is present to the odds of an event occurring if a risk factor is not present.

(a/b) / (c/d) = (a*d)/(c*b)