Use Randomization test for 2-sample means to determine whether the population means of two independent groups differ. You can also use Randomization test for 2-sample means to illustrate important statistical concepts. For observations to be independent, the value of a particular observation does not depend on any previous observation. If your observations are not independent, your results may not be valid. For more information, go to How are dependent and independent samples different?.
For more detail on bootstrapping and resampling techniques, go to What is bootstrapping?
To estimate a confidence interval for the difference in means of two independent groups, use Bootstrapping for 2-sample means.