Pearson's chi-squared test

Pearson's Chi-squared test is a way to figure out if two things are related. For example, if you wanted to figure out if eating ice cream is related to getting colds, you could use this test. The way it works is it looks at the number of people who are eating ice cream and getting colds, and compares it to the number of people who aren't eating ice cream and aren't getting colds. If the numbers are different, then the two things (eating ice cream and getting colds) are related.