1. Why do we care whether the assumptions required forstatistical tests are met?

1. Why do we care whether the assumptions required forstatistical tests are met? (Tip: You might also want to write youranswer on a note card you paste to your computer.) 2. Open the dataset that you corrected in Activity #1 for DownloadFestival.sav. Youwill use the following variables: Day1 Day2 and Day3 (hygienevariable for all three days). Create a simple histogram for eachvariable. Choose to display the normal curve (under ElementProperties) and title your charts. Copy these plots into your Worddocument. 3. Now create probability-probability (p-p) plots foreach variable. This output will give you additional information.Read over the Case Processing Summary. Notice that there is missingdata for Days 2 and Day 3. Copy only the Normal p-p Plots into yourWord document (you do not need to copy the beginning output nor theDetrended Normal p-p Plots). 4. Examining the histograms and p-pplots describe the dataset with particular attention toward theassumption of normality. For each day do you think the responsesare reasonably normally distributed? (Just give your impression ofthe data.) Why or why not? 5. Using the same dataset and theFrequency command calculate the standard descriptive measures(mean median mode standard deviation variance and range) aswell as kurtosis and skew for all three hygiene variables. Pasteyour output into your Word document (you do not need to paste theFrequency Table). What does the output tell you? You will need tocomment on: sample size measures of central tendency anddispersion and well as kurtosis and skewness. You will need toeither calculate z scores for skewness and kurtosis or use thosegiven in the book to provide a complete answer. Bottom line: is theassumption of normality met for these three variables? Does thismatch your visual observations from question #1? 6. Using thedataset SPSSExam.sav and the Frequency command calculate: thestandard descriptive statistics (mean median mode standarddeviation variance and range) plus skew and kurtosis andhistograms with the normal curve on the following variables:Computer Exam Lecture and Numeracy for the entire dataset.Complete the same analysis using University as a grouping variable.Paste your output into your Word document (you do not need to pastethe Frequency Table). What do the results tell you with regard towhether the data is normally distributed? 7. Using the datasetSPSSExam.sav determine whether the scores on computer literacy andpercentage of lectures attended (with University as a groupingvariable) meet the assumption of homogeneity of variance (useLevenes test). You must remember to unclick the split fileoption used above before conducting this test. What does the outputtell you? (Be as specific as possible.) 8. Describe the assumptionsof normality and homogeneity of variance. When these assumptionsare violated what are your options? Are there cases in which theassumptions may technically be violated yet have no impact on yourintended analyses? Explain.

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