What affects sample size?

Question 1

What affects sample size?

Answer 1

Standard deviation of a data set - the narrower the SD, the less important it is to have a large sample size
Power calculation - the ability to detect a difference if one exists
Clinical importance of study

Question 2

What is the advantage of figuring out NNT

Answer 2

Cost benefit is mainly done by using the number needed to treat

Question 3

What is relative risk

Answer 3

Risk in experimental group divided by risk in control group
if RR <1, the intervention reduces the risk of an outcome
If RR>1, the intervention increases the risk of an outcome
if RR = 1, there is no difference

Question 4

What is absolute relative risk

Answer 4

Risk in control group - risk in experimental group

Question 5

What is NNT

Answer 5

1/ARR

Question 6

If RR is 0.28, what does this mean?

Answer 6

There is a 72 percent reduction in an outcome due to this intervention