This document contains a series of exercises related to biostatistics and research methods. It includes exercises on categorizing variables, designing a questionnaire, different sampling methods like simple random sampling, systematic random sampling, stratified sampling and cluster sampling. It also includes exercises on ordering and presenting data in frequency distribution tables, calculating measures of central tendency and dispersion, the normal distribution and confidence intervals. The final exercises are on the chi-square test and t-test, including examples of applying these statistical tests to compare groups.