Common Mistakes in Using Statistics - Spotting Them and Avoiding Them

Please Note:

• Files are in pdf format.
• Most students will want to download the slides and either print them to take notes on in class, or  follow along in class on their laptop. 
• The appendices contain additional material and references. They are available for your reference later according to your own needs.
• Copies of course materials will not be handed out in class. 
• Computers for individual  use will not be available in the classroom for this particular course.
• If you need a different print size or would prefer a .doc file to take notes on, please email me so I can email you .doc files to adjust to your needs. (Please note: Past experience is that .doc files often acquire changes in formatting or symbols when posted on the web; this might also happen with email attachments on some platforms.)

    Day                                             Slides (2 per sheet)                                Appendix

1 (Tues May 26)                                     Slides Day 1                                    Appendix Day 1

2 (Wed May 27)     (Be sure to download all three files for Day 2)             (No appendix for Day 2)

                                                   SlidesDay2Part1(pp. 1-31)             
      
                                                     SlidesDay2Part2(p. 32)

                                                     SlidesDay2Part3(pp. 33-58)

3 (Th May 28)                                  Slides Day 3                                        Appendix Day 3   
                                                            

4 (Fri May 29)                                     Slides Day 4                                    Appendix Day 4                                      

This simulates the results of 100 independent hypothesis tests, each at 0.05 significance level. Click the "test/clear" button  to see the results of one set of 100 tests (that is, for one sample of data). Click the button two more times (first to clear and then to do another simulation) to see the results of another set of 100 tests (i.e., for another sample of data). Notice as you continue to do this that i) which tests give type I errors (i.e., are statistically significant at the 0.05 level) varies from sample to sample, and ii) which samples give type I errors for a given test varies from test to test. (To see the latter point, it may help to focus just on the first column.)

A companion to the preceding website Common Mistakes in Using Statistics. It contains updates to that site and occasional comments on other things related to statistics that come to my attention. It may  be of interest to the following categories of people:

    Teachers of statistics (especially those, such as myself, who come from backgrounds other than statistics)
    Undergraduates and early graduate students in statistics
    Users of statistics (especially people who read research using statistics)

See especially the series of eight "Beyond the Buzz" posts (June 24 - August 26, 2024) discussing two of the articles in the May, 2014 special issue of the journal Social Psychology devoted to registered reports. These posts show how registered replications can exemplify poor practices and thus do not alone solve the problem of  possibly misleading findings.