Compute the confidence interval of the population mean with one sample or of the difference of population means of two samples from normal distributions or t-distributions.Compute the confidence interval of population variance with one sample or of the difference of population variances of two samples by chi-square tests.Test for population mean or the differences of two normal samples under normality with the given null hypothesis H0,which depends on the user,so that he can know if he can reject H0 or not at the significance level alpha.Do the chi-square tests with one or two samples which have multinomial distributions by using an approximate chi-square distribution when n is large enough.
