Question

What is the difference between a t test of independent means and a t test of dependent means? Provide examples of when you would use each type of t test.

Answer 1

The difference between a t test of independent means and a t test of dependent means :

i) when two samples are taken from two independent populations or a group of people is randomly assigned to different groups and then they have gone thorugh different types of experiments, in this case to compare the means, one should use t test of independent means.

example : a group has been randomly divided to two groups and given two drugs A and B.To check the quality of life improved for patients who took drug A as opposed to patients who took drug B?

ii) when same group of people have gone thorigh different types of experiments, then to compare population means, one can use t test of dependent means.

example : one might have tested participants' eyesight (dependent variable) when wearing two different types of spectacle (independent variable).