Key Statistics In EBM

Question 1

Define incidence

Answer 1

Number of new cases of a particular disease arising in a population at risk in a certain time period

Question 2

Define prevalence

Answer 2

All cases of disease existing in a given population at a given time

Question 3

Name some summary analytical measures

Answer 3

Relative risk
Odds ratio
Absolute risk
Mean absolute difference

Question 4

Name some measures of risk

Answer 4

Risk ratio
Odds ratio

Question 5

Define risk ratio

Answer 5

Ratio of incidence rate in group A vs. Incidence rate in group B

RR = Ia / Ib

Question 6

Define odds ratio

Answer 6

Ratio of odds of ‘outcome’ in exposed group vs. Odds of ‘outcome’ in unexposed group

OR = odds of outcome exposed / odds of outcome unexposed

Question 7

Calculate the risk ratio

Answer 7

Question 8

Calculate the odds ratio

Answer 8

Question 9

Define absolute risk

Answer 9

Risk of acquiring a given disease over a given period of time

Question 10

How do you calculate absolute risk difference?

Answer 10

Absolute risk difference = control event rate - intervention event rate

(Or unexposed event rate - exposed event rate)

Question 11

What is p-value?

Answer 11

Expression of statistical significance

Probability that the effect observed could have occurred by chance

Question 12

Answer 12

Question 13

Answer 13