Pardon a relative novice's question.  I'm seeking a reference that describes, compares, and gives formulas for the standard error for ratios and the standard error for differences between means when small Ns are involved.  <br><br>Here is the situation at hand: <br>- Multiple samples from two independent populations.  <br>- The underlying variable is normally distributed in each population, but with somewhat different means and standard deviations. <br>- At least one sample will always be small, perhaps 3 to 15 cases, the other sample will generally be 50 or 100 cases, or even larger. <br>- Statistics of interest: ratio of means and difference between means.  <br>- Question: How will the standard errors of these two sample statistics compare?