This applet simulates using 2x2 contingency tables. The user specifies the population proportions and the sample size. The applet runs simulations using the given parameters. Chi square statistics are generated with and without Yates correction for continuity. This is part of the online statistics book "Online Statistics Education: An Interactive Multimedia Course of Study."
Type of Material:
Simulation java applet augmented with exercises and background material
This works with IE and Firefox
Identify Major Learning Goals:
1. Understand and reinforce chi-square test for independence in 2x2 contingency table.
2. Understand how increasing the sample sizes changes the calculated chi-square.
3. Reinforce understanding p-values.
4. Understand the role of assumptions in hypothesis testing.
Target Student Population:
High school or introductory level college
Prerequisite Knowledge or Skills:
Student should understand what a 2x2 table is and how a Chi-squared test works. They should also understand the principle of simulations.
Evaluation and Observation
The brief content summarizes the material. Yates continuity correction is included. Students can easily create lots of data quickly to explore how concepts work.
Goals of the applet are not well explained. Students will need directions on how to approach the statistical material and what the goals of the applet are. The simulation doesn’t fill in a “2x2” table, but rather it looks more like something used for a two-sample proportion test (while these concepts have much in common, the way we teach them can be different--just something for instructors to be aware of).
Potential Effectiveness as a Teaching Tool
1. Well designed material with adequate explanations of how to use the applet.
2. Supplementary material from the free, online textbook gives additional background to allow a student the opportunity to explore the details.
3. Material can be demonstrated in class with further explorations and examinations assigned for homework.
4. Good reinforcement of the concept of a p-value.
The applet is rather limited in that it only produces a simulation of 2x2 tables and the chi-squared test. If it also included the two-proportion test, this might help students relate the two concepts. Also, if, when simulating 1, if the 2x2 table was output as a true 2x2 table it would be helpful for student visualization. It would also be nice to be able to output a histogram of the p-values or chi-squared statistics so that students can see how they change with different parameters and sample sizes.
Ease of Use for Both Students and Faculty
Nice addition to an interactive lecture. Instructor needs to spend about 5 minutes prior to using the applet to familiarize herself or himself with the material.
The material is not meant to be flashy but rather to reinforce concepts. It adequately meets that goal.
This applet is very useful but not the most engaging. It also doesn’t lead students through concepts to show them how concepts are related. Difficult to resize the material to allow adequate projection in class.