By changing the number of degrees of freedom in a t-distribution, students can see how the pdf changes. They also have the option of overlayng the standard normal curve so that they can see the convergence.
The page calculates summary statistics for any dataset. Users will be prompted for sample size when opening this page. The calculator returns mean, sum of X, sum of X^2, variance, standard deviation, and standard error. Key word: Descriptive statistics.