Epidemiology for the Advanced Practice Nurse: A Population Health Approach
Statistics is all about recognizing and addressing sources of variability, either through study design or statistical analysis. Variability is both essential for understanding associations and a nuisance that encumbers our efforts at measuring them. This chapter provides a description of the properties of variables. Variables are measurable characteristics or traits that vary from object to object. It is useful to classify variables by their scale of measurement. Two goals of research are to characterize attributes or features of a population and assess associations of interest. These activities necessitate the need for observing characteristics of members of a population. Sensitivity can be expressed as the conditional probability that a diagnostic test produces a positive test result given an individual has the disease. Specificity is the conditional probability that a diagnostic test produces a negative test result given an individual is disease free.
Mercante, Donald E., "Biostatistics Primer" (2022). School of Public Health Faculty Publications. 258.