The size of the sample taken in a survey affects how much we can trust the data collected. There are four methods to calculate sample size: for averages, percentages, minimum cell size in a table, and specific differences in a table. These methods help estimate the sample size needed to make sure the information collected is a good representation of the whole population. Even though there is always some error in statistics from sampling, these methods can help determine how big the sample should be and how confident we can be in the results.