Probabilities and Odds Ratio (moodle audio book) 10.12 in book (pg 93)

Question 1

“Odds” meaning

Answer 1

Definition-Odds: The ratio of the probability of an event occurring and the probability of an event not occurring.

Question 2

“Odds” ratio meaning

Answer 2

Definition-Odds ratio: The ratio of two odds.

Question 3

How do you work out Odds

Answer 3

Odds= p/1-p
For example,

Consider the odds of having appendicitis for patients who have severe pain.
The probability of appendicitis with severe pain = 31/59
The probability of no appendicitis with severe pain is 1- 31/59 =28/59
The ratio of the odds is 31/28. (That is 31/59 divided by 28/59)