Support for the
Java 2 runtime environment (version 1.4 or later). Click on the icon to download the appropriate
plug-in.Object Library > Applets > Mean Test Experiment
The experiment is to select a random sample of size n from a selected distribution and then test a hypothesis about the mean µ at a specified significance level. The distribution can be selected from a list box; the options are the normal, gamma, and uniform distributions. In each case, the appropriate parameters and the sample size n can be varied with scroll bars.
The significance level can be selected with a list box, as can the type of test: two-sided, left-sided, or right-sided. The boundary point µ0 between the null and alternative hypotheses can be varied with a scroll bar. The density of the distribution and µ are shown in blue in the first graph; µ0 is shown in green.
The test can be constructed under the assumption that the distribution standard deviation is known or unknown. In the first case, the test statistic has the standard normal distribution; in the second case the test statistics has the student t distribution with n - 1 degrees of freedom. The density and the critical values of the test statistic are shown in the second graph in blue.
On each update, the sample density is shown in red in the first graph and the sample values are recorded in the first table. The sample mean M is shown in red in the first graph and the value of the test statistics (Z or T) is shown in red in the second graph. The variable I indicates the event that the null hypothesis is rejected. On each update, M, Z or T, and I are recorded in the second table. Note that the null hypothesis is reject (I = 1) if and only if the test statistic (Z or T) falls outside of the critical values. Finally, the empirical density of I is shown in red in the last graph and recorded in the last table.
This applet illustrates the following topics and concepts. Click on the links to learn more about the mathematical theory.
Click on the link below to download the Java archive file:
To add the applet to your web page, insert the following in the html file, at the point where you want the applet to appear:
<applet code="edu.uah.math.experiments.MeanTestExperiment.class"
archive="MeanTestExperiment.jar" width="650" height="400"></applet>
The jar file and the html file must be in the same folder.
This width and height dimensions are simply suggestions and can be varied. Generally, components such as graphs and tables expand and contract proportionally, while components such as buttons, scrollbars, dice, and coins are fixed in size.
Support for the
Java 2 runtime environment (version 1.4 or later). Click on the icon to download the appropriate
plug-in.Copyright © 2001-2003 Kyle Siegrist, Dawn Duehring
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.
If you are interested in the Java source code or the Java documentation and object model for this applet, please visit MeanTestExperiment in the Object section of the Library.