2. Pre requisite to for sample size
calculation
Proportion of disease in the case-p0
This extracted from LR, pilot study or assumption(50%
Proportion of disease in the control-p1
This extracted from LR, pilot study or assumption(50%
Ratio of case to control-r( 1;2 or etc)
P-value(-0.05), Z /(1.96)
z is 0.84 at 80% power and 1.28 at 90%
10. example
The proportion who are smoker and hypertensive is 36.2
The proportion who are not drinker and hypertensive is 16.8
Calculate sample size
11.
12.
13.
14. Sample size calculation for case control
Proportion of disease in the case-p0
This extracted from LR, pilot study or assumption(50%
Proportion of disease in the control-p1
This extracted from LR, pilot study or assumption(50%
Ratio of case to control-r( 1;2 or etc)
P-value(-0.05), Z /(1.96)
z is 0.84 at 80% power and 1.28 at 90%