Fundamentals of Statistics contains material of various lectures and courses of H. Lohninger on statistics, data analysis and chemometrics......click here for more. 
Home Statistical Tests Means and Medians TwoSample tTest Small Sample Size  
See also: large sample size, survey on statistical tests, distribution calculator, WelchTest  
TwoSample tTest  Small Sample SizeWhen the sample size is small, the assumption of the central limit theorem does not hold, since the estimates of σ^{2} become unreliable. One therefore has to resort to the tdistribution. The ttest requires some constraints to be fulfilled:
df = df_{1} +df_{2} = (n_{1}1) + (n_{2}1) = n_{1}+ n_{2}  2. In order to apply a twosample ttest you should follow the scheme shown below:


Home Statistical Tests Means and Medians TwoSample tTest Small Sample Size 