# Descriptive StatisticsNMinimumMaximumMeanStd. Deviat.docx

10 de Jan de 2023
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### Descriptive StatisticsNMinimumMaximumMeanStd. Deviat.docx

• 1. Descriptive Statistics N Minimum Maximum Mean Std. Deviation total 105 50 125 100.07 14.483 Zscore(total) 105 -3.45694 1.72157 .0000000 1.00000000 Valid N (listwise) 105 Question 1 What is the sample mean (M) and sample standard deviation (s) for total? You will use these values in Question 2 below. [Answer here in complete sentences. Also insert the output from SPSS here. Replace this prompt and the prompts below, using as much space as necessary to answer questions.] Question 2
• 2. A z score for this sample is calculated as [(X – M) ÷ s]. Locate Case #53’s unstandardized total score (X) in the Data Editor. In the formula below, replace X, M, s, and ? to show how the z score in Ztotal is derived for Case #53. (X – M ) ÷ s = ? Question 3 Run Descriptives… on Ztotal. What are the mean and standard deviation of Ztotal? (Hint: “0E7” in SPSS is scientific notation for 0). Are the mean and standard deviation what you would expect? Justify your answer. [Answer here in complete sentences. Also place the SPSS output here.] Question 4 Case number 6 has a Ztotal score of 1.51. What does a z value of 1.51 represent? [Answer here in complete sentences.] Question 5 Identify the case with the lowest z score. Refer to Appendix A in the Warner (2013) text. Interpret the percentile rank of this z score rounded to whole numbers. [Answer here in complete sentences.] Question 6 Identify the case with the highest z score. Refer to Appendix A in the Warner (2013) text. Interpret the percentile rank of this z score rounded to whole numbers. [Answer here in complete sentences.] Section 2: Cases Studies of Type I and Type II Errors Question 7 A jury must determine the guilt of a criminal defendant (not guilty, guilty). Identify how the jury would make a correct decision. Analyze how the jury would commit a Type I error versus a Type II error. [Answer here in complete sentences.] Question 8 An I/O psychologist asks employees to complete surveys measuring job satisfaction and organizational citizenship
• 3. behavior. She intends to measure the strength of association between these two variables. The researcher is concerned that she will commit a Type I error. What research decision influences the magnitude of risk of a Type I error in her study? [Answer here in complete sentences] Question 9 A clinical psychologist is studying the efficacy of a new drug medication for depression. The study includes a placebo group (no medication) versus a treatment group (new medication). He then measures the differences in depressive symptoms across the two groups. What would a Type I error represent within the context of his study? How can he reduce the risk of committing a Type I error? How does this decision affect the risk of committing a Type II error? [Answer here in complete sentences.] Section 3: Case Studies of Null Hypothesis Testing Question 10 You are running a series of statistical tests in SPSS using the standard criterion for rejecting a null hypothesis. You obtain the following p values. Test 1 calculates group differences with a p value = .07. Test 2 calculates the strength of association between two variables with a p value = .50. Test 3 calculates group differences with a p value = .001. For each test below, state whether or not you reject the null hypothesis. For each test, also explain what your decision implies in terms of group differences (Test 1 and Test 3) and in terms of the strength of association between two variables (Test 2). Test 1 (group differences) = Test 2 (strength of association) = Test 3 (group differences) = Question 11 A researcher calculates a statistical test and obtains a p value of .86. He decides to reject the null hypothesis. Is this decision
• 4. correct, or has he committed a Type I or Type II error? Explain your answer. [Answer here in complete sentences] Question 12 You are proposing a research study that you would like to conduct while attending Capella University. During the proposal, a committee member asks you to explain in your own words what you meant by saying “p less than .05.” Provide an explanation. [Answer here in complete sentences] References Provide references if necessary. This concludes Unit 4 Assignment 1. Save your answers and upload this template to the assignment area.