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The One sample item on the T Statistics submenu on the Stat menu provides confidence intervals and/or hypothesis tests for a population mean when the population variance is not known. The results are displayed in the Results panel.
In the dialog box, select the variable to be analyzed. This procedure is illustrated using the Old Faithful data.
Click the Next -> button to select either a confidence interval (specifying confidence level) or a hypothesis test (specifying null mean and alternative hypothesis). In the Old Faithful example, it is of interest to estimate the mean interval between eruptions.
Click on the Calculate button and the output, consisting of the estimated mean, standard error, number of degrees of freedom, and upper and lower confidence limits, is displayed in the Results panel. In the testing case, the output consists of the null hypothesized value for the mean ("MU0"), the estimate of the mean, its standard error, the number of degrees of freedom, the T statistic, and its associated p value.
