The Probability Calculator is used to understand visually what select probability mass/density functions look like graphically, including both continuous and discrete distributions with user defined parameters and calculates cumulative probabilities.
Type of Material:
Simulation
Recommended Uses:
This site would be beneficial for in class visualization for professors that want to compare the shape of distributions with several different parameters.
Technical Requirements:
The technical requirement for the probability calculator is a working internet browser. Also, flash needs to be installed.
Identify Major Learning Goals:
The goal of this site is to visually understand how changing parameters will affect different distributions
Target Student Population:
Probability classes studying various probability distributions and
Math Stats classes. Undergraduate or graduate students.
Prerequisite Knowledge or Skills:
Formulas for distributions are prominent on web site. Recommended for students who are comfortable with formulas and integration for the continuous distributions. A basic understanding of probability mass/density functions is necessary to fully understand the graphs presented.
Content Quality
Rating:
Strengths:
The graphs seem appropriate and accurate for all distributions. Both axis and parameters can be adjusted. This is a very simple to use tool that draws associated graphs of typically studied probability distributions. Little to no set-up time is required for an instructor to use. While the formulas are prominent, the graphical display is the important aspect.
Concerns:
The instructor needs to pay attention to using correct parameters and variable values. For example, if the user enters a parameter or value for a variable incorrectly, no error message is given. The graph is drawn with the mistake. For example, the graph for the chi-squared distribution will be drawn from -3 to 3. The correct cumulative probability (x greater than user supplied value) is calculated, but the graph shows area under the curve when x is less than 0. Also, there were typographical errors on the first page, probably instead of probability.
Potential Effectiveness as a Teaching Tool
Rating:
Strengths:
The goal of this web site is only to demonstrate the probability distributions. Expectations of conceptual understanding to be developed should be limited to having students explore how distributions change as the parameters of that distribution changes. The site is quite useful in this limited goal. This module can help in the visualization of distributions and the effect of changing parameters.
Concerns:
Although the module grouped like distributions, it could better explain or demonstrate the relationship between the distributions. Although a great demonstrative tool, I do not think it allows the student to develop critical thinking skills.
Ease of Use for Both Students and Faculty
Rating:
Strengths:
This module is very easy to use and does explain the different parameters. The instructions were very clear and it is very interactive for the user.
Concerns:
The font, being Times New Roman is often hard to read on a computer screen and perhaps a font that is san serif would be more easily read.
Creative Commons:
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