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.
January 26, 2010 webinar presented by Alicia Gram, Smith College, and hosted by Leigh Slauson, Capital University. This webinar describes an activity that uses data collected from an experiment looking at the relationship between two categorical variables: whether a cotton plant was exposed to spider mites; and did the plant contract Wilt disease? The activity uses randomization to explore whether there is a difference between the occurrence of the disease with and without the mites. The webinar includes a discussion of the learning goals of the activity, followed by an implementation of the activity then suggestions for assessment. The implementation first uses a physical simulation, then a simulation using technology. (Extra materials, including Fathom instructions for the simulation, available for download free of charge).