Of 26.8.Unstacked data: The quantitative data is distributed across the groups in multiple columns. For example, the first row is a brown-eyed person with a CFF The first two columns show the data in a stacked format.Įach variable is a column (one column for the explanatory variable eyeĬolor one column for the response variable CFF) and each row is an In this spreadsheet the data is presented in two formats.Stacked data: The quantitative data is stacked in one column. The mean critical threshold frequency is important for product manufacturing as well as tests for ocular disease.In 1973, researchers conducted a study to answer the following question.Research question: Do people with different eye color have different threshold flicker sensitivity?The 1973 study (“The Effect of Iris Color on Critical Flicker Frequency,” Journal of General Psychology, 91–95) obtained the following data from a random sample of 19 subjects. The flicker, and it is annoying!Different people have different flicker “threshold” frequencies (known as the critical flicker frequency, or CFF). If theįrequency of the flicker is below a certain threshold, the eye detects A list of StatCrunch directions is provided at the bottom of this page.ContextCritical flicker frequency (CFF) and eye colorComputer screens and fluorescent bulbs flicker. We highly recommend that you complete this activity on aĬomputer.Here are the directions and grading rubric for the discussion board exercises. He has also published extensively in the fields of changepoint analysis and toxicological risk assessment.Learn by DoingThe purpose of this activity is to give you guided practice in carrying out the ANOVA F-test using StatCrunch.Some features of this activity may not work well on a cell phone or West has numerous research interests most of which (not surprisingly) involve a fair amount of statistical computing. Currently, he is a Principal Investigator (with Roger Woodard) of the National Science Foundation funded Improving National acceptance of Computing Intensive Statistical Techniques (INCIST) project that is developing, field testing, and disseminating computationally intensive materials for teaching the topics in an introductory statistics course. In 2005, he received the CAUSEweb Resource of the Year Award and the Merlot Classics Award for the StatCrunch project. With support from the National Science Foundation, his StatCrunch package has now blossomed into one of the most used statistical resources on the Web. In the same vein, he began to develop a complete online data analysis package in 1997. To date, he has developed more than 50 such applets, many of which now accompany introductory statistics textbooks. In the mid 1990s, he started to construct interactive web-based java applets that help students understand difficult statistical concepts. West began developing Internet resources for statistical education. Shortly after completing his PhD in Statistics at Rice University in 1994, Dr.
Webster West is a professor of Statistics at North Carolina State University.
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