170717P - PRINCIPLES OF EPIDEMIOLOGY HEALTH RESEARCH COURSE: DISCRETE DATA ANALYSIS

Presentation at a Course on Principles of Epidemiology Health Research Faculty of Medicine, King Fahad Medical City October 11-12, 2017 by Professor Omar Hasan Kasule Sr. MB ChB (MUK). MPH (Harvard), DrPH (Harvard) Chairman of the Institutional Review Board / Research Ethics Committee at King Fahad Medical City, Riyadh.

LECTURE # 8 DISCRETE DATA ANALYSIS

SIMPLE ANALYSIS OF PROPORTIONS:

• Inference on discrete data is based on the binomial/multinomial distribution. 

• It uses 2 approximate methods (z-statistic and the chi-square) used for large samples and one exact method (Fisher's Exact Method) used for small samples. 

• Approximate methods are accurate for large samples and are inaccurate for small samples. There is nothing to prevent exact methods from being used for large samples. 

STRATIFIED and MATCHED ANALYSIS OF PROPORTIONS:

• The Mantel-Haenszel chi-square is used to test 2 proportions in stratified data. 

• The MacNemar chi square is used for pair matched data.

EXACT ANALYSIS OF PROPORTIONS:

• Exact methods are used instead of the chisquare test for small samples less than 20.

• They involve direct computation of the p-value using factorials and probability.