Jomo Kenyatta University of Agriculture and Technology
biometrics
STATISTICS 304

Summer 2016
SAS 415: BIOMETRIC MODELS
LECTURE NOTE
BY Richard Wachana
Relative risk (RR)
This is the ratio of the probability of an event (outcome) occurring (such as
developing a disease or being injured) in an exposed group to the probability of the
event occurring
Jomo Kenyatta University of Agriculture and Technology
biometrics
STATISTICS 304

Summer 2016
SAS 415: BIOMETRIC MODELS
LECTURE NOTES
By Richard Wachana
OUTBREAK INVESTIGATION
When disease incidence departs from expected patterns, applied epidemiology
mounts outbreak investigation. Outbreaks are studied for several reasons.
To determine etiology
Jomo Kenyatta University of Agriculture and Technology
biometrics
STATISTICS 304

Summer 2016
SAS 415: BIOMETRIC MODELS LECTURE NOTES
RICHARD WACHANA
Odds Ratio (OR)
This is another measure that used to quantify the strength of association between
variables (disease and exposure).
In 2x2 tables, suppose the probability of success is
Within Row 1,
Jomo Kenyatta University of Agriculture and Technology
biometrics
STATISTICS 304

Summer 2016
SAS 415: BIOMETRIC MODELS
LECTURE NOTES
By Richard Wachana
CAUSALITY
Epidemiological research often seeks to identify whether there is a causal
relationship between the risk factor and the disease. The first stage in investigating
causality is to establis