Textbook: Field, A. (2013). Discovering statistics using IBM SPSS Statistics (4th ed.). London, England: Sage.
Assignment on Assumptions
Submit one Word document for this assignment (copy and paste SPSS output into the Word document). All datasets can be found on the textbook companion website at http://www.sagepub.com/field4e/study/datasets.htm under the file name Andy Field’s Datasets.
1. Festival Histogram: Using the file DownloadFestival.sav, beginning with section 5.3.1 in the text on spotting outliers, correct the typo in the data as directed, create a separate histogram for each day, Day1, Day2, and Day3, using the hygiene variable for all three days. Include the normal curve (found under Element Properties), and title each chart. The results should resemble Figure 5.13 on page 182. Copy each one to the Word document with an appropriate title for each. (10 pts.)
2. Festival Descriptives: For the same dataset, use the Frequency command to calculate the standard descriptive measures (mean, median, mode, standard deviation, variance, and range) as well as kurtosis and skew for all three days/hygiene variables. Copy the output to the word document with an appropriate title. You do not need to copy the Frequency Table. (10 pts.)
3. Festival Output: Comment on the sample size, measure of central tendency, dispersion, kurtosis, and skewness. Use the z-scores in the book (or calculate your own) to provide this response. What does the output tell you? (15 pts.)
4. Festival Normality: Is the assumption of normality met for these variables? (5 pts.)
5. Exam Descriptive Statistics: Using the dataset SPSSExam.sav, and the Frequency command, calculate the standard descriptive statistics (mean, median, mode, standard deviation, variance, and range) plus skew and kurtosis, and histograms with the normal curve on the variables Computer, Exam, Lecture, and Numeracy for the entire dataset. Copy the output to the Word document with an appropriate title. (10 pts.)
6. Exam Grouping Variable: Complete the same analysis using University as a grouping variable. Copy the output to the Word document with an appropriate title. You do not need to copy the Frequency Table. (10 pts.)
7. Exam Data: What do the results tell you with regard to whether the data is normally distributed? (10 pts.)
8. Homogeneity: Using the dataset SPSSExam.sav, determine whether the scores on computer literacy and percentage of lectures attended (with University as a grouping variable) meet the assumption of homogeneity of variance (use Levene’s test). You must remember to unclick the “split file” option used above before doing this test.
a. What does the output tell you? (Be as specific as possible.) (10 pts.)
9. Assumptions: Describe the assumptions of normality and homogeneity of variance. (10 pts.)
10. Assumptions / Options: When these assumptions are violated, what are your options? (5 pts.)
11. Violated Assumptions: Are there cases in which the assumptions may technically be violated, yet have no impact on your intended analyses? Explain. (5 pts.)
