You can use either data format choose one (stacked data in the first two columns or unstacked data Use StatCrunch to create side-by-side dotplots, histograms orīoxplots (your choice) to examine the distribution of CFF scores forĮach sample. Scores for each sample (because the samples are small). To verify conditions, you will need to examine the distribution of CFF Also, the StatCrunchĭirections are provided in the list a the bottom of this page.What are the hypotheses for the ANOVA test? Be sure that you define clearly the parameters.Īre the conditions that allow us to safely use the ANOVA F-test met? Explain.Note: The flickerĭatafile is available in the Data section below. use the Data below PromptWe will conduct an ANOVA F-test for the variables Color and CFF. The quantitative data represents the frequency threshold at which the subject sees the flicker. The categorical data represents the groups we will compare.CFF (flicker threshold sensitivity): This is the response variable. Each columnĬontains the response values (CFF) for that group.The format of the data in the spreadsheet affects how we use StatCrunch to analyze it.VariablesColor: This is the explanatory variable. In this format, each column is a group defined by a value of theĮxplanatory variable: one column for blue-eyed people, one column forīrown-eyed people and one column for green-eyed people. The last three columns show the same data in an unstacked format. 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. 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
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