What is the primary purpose of a t-test in analytical chemistry?

What is the formula for calculating the t_score when the population standard deviation is unknown?

How are degrees of freedom calculated for an equal variance t-test with two samples of sizes 12 and 15?

What is the role of the pooled standard deviation in an equal variance t-test?

Design an experiment using a t-test to compare the average test scores of two different teaching methods, where one method is a traditional lecture.