The t-test for independent groups otherwise known as student’s t-test or unpaired t-test, is a statistical test for determining the significant difference of the means of two unrelated or correlated groups.
The t-test was invented by William Sealy Gosset. As a chemist, he used the t-test to handle small samples for quality control in brewing. He wrote published his works under the name “Student”, thus the term student’s t-test.
In this example we provide a hypothetical data of the Biological Oxygen Demand (BOD) of two rivers. We will then perform a t-test in order to determine if the two rivers are significantly different in terms of BOD.