Student’s t-Test for Independent Samples

The purpose of this lesson is to use R to examine differences between groups, specifically by using Student’s t-Test for Independent Samples. Overall, Student’s t-Test is a very common test for determining differences when a singular measured variable (e.g., IQ score, weight of dairy cow milk production per lactation, length of shark dorsal fin, etc.) is compared to differences between a grouping variable with two breakout groups (e.g., Female v Male humans, Guernsey v Jersey cows, Mako v Great White sharks). The t-Test was developed in the early 1900s by Gosset, as part of quality assurance work for a beverage company, but writing under the pen name Student. Student’s t-Test is the appropriate test for comparing differences between small samples, typically 30 or fewer, as opposed to samples with more than 30 observations.