In addition, the t-test requires equality of variances as Jake pointed out. The t-test for equality of means is a sad example of a test that is taught because it can be done in closed form on a blackboard rather than because its conditions actually obtain in real life. Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
It is not at all obvious that the ratio of indictees to civilians in that case should follow any given distribution, for instace a Gaussian. Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
