Odds and probabilities

Question 1

Probability

Answer 1

• relative frequency of occurrence of a given event over s sequence of unlimited random trials done under similar conditions
• compares the number of events of interest to the total number of trials during which the event may occur
• can be any value between 0 an 1

Question 2

Probability values

Answer 2

-can only be values between 0 and 1 or percentage

Question 3

Probability of a complementary event

Answer 3

• probability of an event not occurring

- p=(1-p)

Question 4

Odds

Answer 4

• ratio of the frequency that an event occurs to the frequency that it does not occur
• compares the number of events of interest to the number of other events in the trial

Question 5

Odds ratio

Answer 5

• work out probability of each occurrence
  e. g P(heads)=n(heads)/No tosses
• Odds of heads= n(heads)/n(tails)
• Odds= Probability/1-probability
• Probability= odds/1+odds

Question 6

Equations

Answer 6

P(A)=n(A)/N
P(B)=n(B)/N
Odds of A= n(A)/n(B)
Odds of B= n(B)/n(A)