This site contains simulations on a multitude of distributions, interactive graphs, games and mappings of different distributions used to help visualize and understand distributions, their parameters and relationships to other functions.
The learning goals of this site are to better visualize distributions, how they are affected by their parameters, and how they are related to other distributions. The applet is so general that it could be used for several different learning goals. For example, seeing if a normal curve is a good fit to data. Or demonstrating Fourier fits.
Target Student Population:
The target population is undergraduate or graduate level math or statistics courses.
Prerequisite Knowledge or Skills:
A good understanding of the distributions used is necessary to adequately use this site.
Type of Material:
The type of material is a collection of simulations and java applets.
Recommended uses for this applet would be for in class lecture visualization aids or as a reference for students for outside work.
Technical requirements include Java and a browser that allows for pop-up windows.
Evaluation and Observation
The list of possible distributions is large. The graphs are well presented. The site is very visually appealing and highly interactive.
It was not always consistent in content. The user was taken to multiple pages and websites to find information about the module. The user is left to do much interpretation and manipulation without a great deal of guidance from the site.
Potential Effectiveness as a Teaching Tool
The plethora of functions and distributions able to be used allow for a wide range of simulations. There are portions of the site that allow for user input of data, simulation of data, or general trends the distributions follow. The distributome is highly interactive.
There is a lack of information given to the users, so unless they fully comprehend the site and particular parts in which they are using, it may be difficult to fully and accurately interpret the results. Although the site is very visual, it is not as effective assessing student learning but rather lends itself to students that have already learned material and are able to use the site effectively. The distributome is helpful to see how distributions are related, but it can get overbearing with so many. Also, it may be helpful for some to see not only the PDF/PMF but also E(X) or Var(X) for each distribution.
Ease of Use for Both Students and Faculty
No matter which modeler you are using, the setup of the screen is the same. So once you have figured out the controls, you do not have to learn new ones. Modules had both a scale to pick a parameter value, as well as a place for the user to enter in their own value if not contained in the scale.
The user seemed to need to visit several sites before finding out how to use a certain module or tool. Also, the different links went to different sites. It is a lot of work to have everything in one site, but it makes it more consistent. It was also hard to find answers to questions when needing to sift through the multitude of information. Perhaps if the “help” button displayed information similar to the “about” button, in a concise and uniform manner, users would have an easier time navigating through the site. The module was also very complex and was not always clear what the user was supposed to do. It may also be helpful to define the user defined parameters so the user would know what to with them. When looking at “functions” – the user may use PDF/CDF, however they are never told what the PDF nor CDF are. There is more space in the yellow/tan box below the interactive graph and I think it might be helpful to add the functions used in that space. Even on individual pages (for example the games page) the “help” and “about” buttons are not consistent, and a new button “I” is given and it’s not exactly clear that it is also a help button (i.e. information). More consistency throughout the pages would be great as well as defining some of the buttons (i.e. the “i” and arrow buttons for the games page).
Other Issues and Comments:
I couldn't figure out how to change the x-axis. I can zoom in and out, but zero is always in the middle of the graph. I think the site has great potential, but clearer directions and an easily manipulated interface would be more helpful.