# HK 44500 Chapter Notes - Chapter 4: Case Series, Relative Risk, Randomized Experiment

## Document Summary

Applications: tables, graphs, numerical summary measures. Functions: provides information, identifies greatest risk, identifies extent of risk, provides clues to identify health effect, obtains description, assists in planning, future research. Nominal data: unordered categories or classes, categorical (qualitative, ex. Gender, race/ethnicity, marital status: graphs: bar chart, spot map, area map. Ordinal data: categorical, severity levels: 1 4 (minor fatal, graphs: bar chart. Discrete data: numeric (quantitative, graphs: bar chart, ex. Continuous data: numeric (quantitative, not restricted, graphs: histogram, box plot, stem-and-leaf plot, ex. Epidemic = in excess of normal expectancy. Point prevalence proportion: ppp = new and existing cases of the disease or event at a point in time x 10^n. Total study population at a point in time. Secondary attack rate: rate of new cases occurring among contacts of known cases. Crude rates: calculated without restrictions, compare them between subgroups, potential confounding influences. Age-adjusted rates: more accurate comparison, two methods, direct.