**National Library of Virtual Manipulatives: Box Plot

An interactive box plot applet that allows users to put in their own data that is part of a large collection of platform independent, interactive, java applets and activities for K-12 mathematics and teacher education.
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Author Name: 
Cannon, Cannon, Dorward, Duffin, Heal, Stowell, Susman, Wellman, Youngberg
Content Quality Concerns: 
The calculation of standard deviation is based on a divisor of n when determining the variance. This is not a problem, but should at least be pointed out. It is not clear what rule the software is using to determine quartiles. It is not the usual rule used in K-12 statistics, which excludes the median from both the lower and upper "halves" when n is odd. In the boxplot window, the mean appears to be marked in red below the boxplot, and an interval about the mean is displayed in green. A description of the interval is not provided and the meaning of the interval is not clear.The interval appears to be: Mean +/- (.5)(Standard Deviation).
Content Quality Strengths: 
Interactive nature of the material would allow this to be a great demo in class. The overall clarity of presentation of the graphs, the easy to read numerical summaries, the ability to adjust cell widths would enable a lecturer to generate a lot of discussion with the few well chosen data sets.
Ease of Use Concerns: 
When you clear the data using the clear button the information is lost immediately. This can be problematic if the user has entered a large number of values and accidentially hits clear.
Ease of Use Strengths: 
Very easy to learn to use, intuitive and obvious. The instructions provided will be helpful for those who may not be familiar with interactive web sites or who may miss some of the possible mouse overs. (Note: the instructions are entitled "Boxplots" but contain instructions for the histograms, too.) Connections are shown to the Math Standards will be useful in a pre-service teacher class.
Potential Effectiveness Concerns: 
It would be useful to examine the effect of unusual data points on the range (if added) and the IQR (if added) and compare these with their effect on the standard deviation. Also, it would be useful if both the boxplot and histogram could be shown in the same window for an easier comparison. Finally, the teacher information might provide more guidance in how to connect the numerical summaries and the graphical representations.
Potential Effectiveness Strengths: 
Data provided illustrate strengths and weakness of histograms and boxplots. Additional points can be added or given points deleted to see the changes which occur in the plots and the numerical summaries.
Content Quality Rating: 
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Potential Effectiveness Rating: 
Source Code Available: 
Source Code Available
Intended User Role: 
Learner, Teacher
Resource Type: 
Free for All

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