Greg DePersio has 13+ years of professional experience in sales and SEO and 3+ years as a writer and editor. Simple random sampling is a method used to cull a smaller sample size from a larger ...

Among the most common types of experiments are comparative studies that contrast outcomes under different conditions such as male versus female, placebo versus drug, or before versus after treatment.

The results of the third phase of the HapMap study, which looks at genetic variation in multiple populations, have just been published. Researchers looked at 1184 samples from 11 populations to ...

Categorical Variable: the variable whose values can be put into categories (groups). Cluster Sampling: a researcher divides the population into clusters. Then, a simple random sample of the clusters ...