The document explains the one-sample Wilcoxon test, which is used to determine if a sample is statistically similar to or different from a population. It provides an example comparing IQ scores, where researchers took a random sample of 20 people and want to know if the sample's mean of 70 is representative of the overall population's mean of 100. The one-sample Wilcoxon test compares the sample and population medians to determine the probability that the sample and population are statistically similar or different.