This applet builds confidence intervals for the percentage of orange candies in box with two colors of candies. A smaller box visualizes the sample, and a graph keeps track of the location of the confidence interval. Students can take one sample (producing one CI) repeatedly, or take 100 random samples at once. The population percentage is hidden from view unless the student asks to see it, in which case it is displayed on the graph of confidence intervals. This allows the students to see whether each interval "hits" or "misses". Several parameters can be varied: sample size, confidence level and number of samples. A set of questions alongside the applet guides students.
Java, web browser
Content Quality Strengths:
The applet is very easy to use, and has very clear graphics. The idea of drawing a sample from a bin of colored marbles is simple and easy for students to grasp. The visual of the bin is good for helping students connect the calculated percentage to a physical entity. Having the parameter re-set to a different unknown value is also a valuable conceptual tool.
Ease of Use Strengths:
The applet is simple and visually appealing. The instructions and questions to consider are well written. The applet is very easy to use with very little or no instruction.
Potential Effectiveness Strengths:
The applet has clear instructions and good questions to consider. It is simple to use and clearly demonstrates a couple of key statistical concepts. Overall, this can be a useful applet.
Potential Effectiveness Rating:
Source Code Available:
Source Code Available
Intended User Role:
Free for All