ChiSquare Goodness of Fit Day 2 (Topic 8.3)
Chapter 12  Day 2
Learning Targets

Perform a chisquare test for goodness of fit.

Conduct a followup analysis when the results of a chisquare test are statistically significant.
Activity: Which Color M&M is the Most Common? – Part Two
Stats Medic / Skew the Script Collaboration Lesson: Does Harvard Discriminate Against Asian Applicants? (Pt 2)
For this activity, we will be using the M&M data collected yesterday. Students should have enough information and knowledge to be able to construct a 4step significance test without much of your help at all.
Common Student Error
Students are used to the degrees of freedom formula n – 1 from onesample t procedures. But there is a big difference here. For onesample t procedures, n represents the sample size. For a chisquare test for goodness of fit, n represents the number of categories.
Follow Up Analysis
A followup analysis is only suggested if the data are statistically significant. If the data are not statistically significant, there is no reason to do further analysis.
Over the years, several free response questions have required students to perform a chisquare significance test. The followup analysis is not required for full credit when performing the test, but the thinking involved in the followup analysis may help students succeed in part (b) of the question. See 2008 #5 and 2016 #2.
We have our students add a follow up analysis sentence at the end of the conclusion for any chisquare test with statistically significant data.