why is it important to conduct a t-test what t test is used to test for homogeneity when conducting a t-test why would one prefer to assume (or test for) equal variances rather than always use a welch approximation of the df? which df is used for t tests? when performing a t test what is the best approximation which is preferable when welch adjusted t test how does a welch adjusted t test work why should one assume a different test than a welch adjusted test? why do people use welch adjusted t test instead of df what is standard deviation of welch test what is the difference between a welch adjusted t-test and a standard t-test? why is it important not to use a welch adjusted t test why do welch adjusted t tests always use df why assume df variance instead of welch why do t-test tests always test for equal variance why do welch adjusted t tests always show homogeneity what is meant if the t test is always used why welch adjusted t why do welch adjusted t-tests always show the same results how to test df