This document discusses sample size calculations for research studies. It covers the formula for calculating sample size for infinite populations, how to modify the sample size by adding a design effect and non-response rate. It also discusses using online calculators and calculating sample size for finite populations and qualitative studies. Participants will learn about sample size calculations and practice calculating sample size for different research studies varying confidence levels, proportions, precision levels, design effects, and non-response rates. The document emphasizes that saturation is key for qualitative sample size but some common rules used are 5 key informant interviews, 30 in-depth interviews, and 1 focus group per group.