Short summary on the main features and detailed description of an applet.
The site we were assigned to summarize, Web-enhanced Introductory Statistics Courses at West Virginia (http://www.stat.wvu.edu/SRS), is an on-line program offering two statistics courses for students to take completely on line. The student reads, sees examples, and completes exercises on line, e-mails them to the instructor whereupon the instructor grades and returns the student's graded answers along with the instructors answers via e-mail.
As a whole, we thought this was a great concept. The two courses available are Stat 101 and 102. The 101 course is very elementary, introducing the very simplest concepts and terms used in statistics. The second course goes through the more advance topics that would be presented in a Stat 3000 class. The text was written plainly, there were interactive examples and exercises for students to complete.
We didn't find this site very intuitive to use. The interactive examples and exercises were not easy to manipulate without reading the papers we received about this site. But it is a relatively new site (created in 1977) and is still under construction. In fact, we ventured into an area that was under construction and locked up the terminal.
There is an applet example of confidence intervals that we found interesting. At first, we couldn't figure out what it was about; but after reading the paper, "Learning Statistical Concepts Using Web-based Dynamic Graphics," by Wojciechowski and Harner, it was clear what this interactive example was trying to demonstrate. There are 100 samples taken from a normal distribution of size n - which can be altered by the user. 100 confidence intervals are represented on the screen along with the population parameter (m). If the confidence interval contains m, then the interval is shown in blue. If the confidence interval doesn't contain m, then the interval is yellow. Thus, a student can see that the total number of intervals containing the true population parameter is approximately 100(1-a)%. The user can manipulate n, m, and a. We thought this was a very good demonstration of what is meant by a confidence interval.
Another applet we managed to figure out how to use was the one demonstrating the normal distribution. In this applet a student could look at a one-tailed, or two-tailed probability distribution and get the probability both visually and numerically. Both the cdf and pdf could be viewed and the parameters could be changed. This wasn't as interesting as confidence intervals, but for the beginning statistics student, this was a good demonstration of a normal probability distribution.
All in all, this seemed to be a very simple site. There wasn't a great deal of information offered or additional links available as this is a course WebPage. But in its simplicity came a clear introduction to basic statistical concepts. Some of the navigational tools need work and the site needs to be completed before it will really be up to par.
Roxanne Drachenberg
(435) 752-8375
roxanned@pcu.net
&
Weiping
weipingdeng@cc.usu.edu