NORMAL DISTRIBUTION
Standard Error of Sample Means. The means of samples of size n, randomly drawn from a normally distributed source population, belong to a normally distributed sampling distribution whose properties are determined by the parameters of the source population. This page will calculate and graphically display the standard error of any particular sampling distribution of sample means, given the mean and standard deviation of the source population, along with the value of n.
Standard Error of the Difference Between the Means of Two Samples. The difference between the means of two samples, A and B, both randomly drawn from the same normally distributed source population, belongs to a normally distributed sampling distribution whose overall mean is equal to zero and whose standard deviation ("standard error") is determined by the variability of the source population and the respective sizes of the two samples. This page will calculate and graphically display the standard error of any particular sampling distribution of sample-mean differences, given the mean and standard deviation of the source population, along with the values of na and nb.