Question

QUESTION 13

Below are the data (n=100) from a randomized trial designed to evaluate the effectiveness of a newly developed pain reliever designed to reduce pain in patients following joint replacement surgery. The trial compared the new pain reliever to the pain reliever currently in use (called the standard of care).  The outcome of interest was reduction of pain rating (3 or more scale points are considered a clinically meaningful reduction).

	clinically meaningful reduction in pain	no clinically meaningful reduction in pain
new pain reliever	33	17
standard pain reliever	30	20

What is the probability of experiencing a clinically meaningful reduction in pain given that the patient received the new pain reliever? (express this probability as a decimal between 0 and 1)

4 points   

QUESTION 14

What is the probability that a patient in this trial received the new pain reliever, given that they experienced a clinically meaningful reduction in pain? (express this probability as a decimal between 0 and 1)

Answer 1

Q 13)

The Probability of experiencing a clinically meaningful reduction in pain given that the patient received the new pain reliever =

P( new pain reliever and experiencing a clinically meaningful reduction in pain)/ P( patient received the new pain reliever) =

= 33/50= 0.66

Q 14)

The Probability that a patient in this trial received the new pain reliever, given that they experienced a clinically meaningful reduction in pain

= P( a patient in this trial received the new pain reliever and experienced a clinically meaningful reduction in pain)/ P( a patient experienced a clinically meaningful reduction in pain)

= 33/63 = 0.5238