Scenario: Imagine you are a researcher who believes that a relaxation technique involving visualization will help people with mild insomnia fall asleep faster. You randomly select a sample of 20 participants from a population of mild insomnia patients and randomly assign 10 to receive visualization therapy. The other 10 participants receive no treatment.
You then measure how long (in minutes) it takes participants to fall asleep. Your data are below. The numbers represent the number of minutes each participant took to fall asleep.
| No Treatment (X1) |
Treatment (X2) |
| 22 |
19 |
| 18 |
17 |
| 27 |
24 |
| 20 |
21 |
| 23 |
27 |
| 26 |
21 |
| 27 |
23 |
| 22 |
18 |
| 24 |
19 |
| 22 |
22 |
Assignment:
• Explain whether you chose to use an independent-samples t test or a matched-samples t test. Provide a rationale for your choice.
• Identify the independent and dependent variables.
• Knowing you believe the treatment will reduce the amount of time to fall asleep, state the null and alternate hypotheses in words (not formulas).
• Explain whether you would use a one-tailed or two-tailed test and why.
• Explain whether you have homogeneity of variance, and explain how you know. Explain why it is important to know if you have homogeneity of variance.
• Identify the obtained t value for this data set using SPSS.
• Identify the degrees of freedom and explain how you determined it.
• Identify the p value.
• Explain whether you should retain or reject the null hypothesis and why.
• Explain what you can conclude about the effectiveness of visualization therapy.
• Submit three documents for grading: your text (Word) document with your answers and explanations to the application questions, your SPSS Data file, and your SPSS Output file.
• Provide an APA reference list.
Resources:
Readings-
• Heiman, G. (2015). Behavioral sciences STAT 2 (2nd ed). Stamford, CT: Cengage..
o Chapter 8, "Hypothesis Testing Using the One-Sample t-test" (pp.126-138)
o Chapter 9, "Hypothesis Testing Using the Two-Sample t-test" (pp.140-158)
o Chapter 9 Review Card (p. 9.4)
Media
• StatsLectures. (2011a). SPSS - Dependent samples t-test [Video file]. Retrieved fromhttp://www.youtube.com/watch?v=DzitbJHIBQMNote: The approximate length of this media piece is 4 minutes. This resource can help you determine a dependent-samples t test from sample data in SPSS.
• StatsLectures. (2011c). SPSS - Independent samples t-test [Video file]. Retrieved fromhttp://www.youtube.com/watch?v=VUUfBWlziIUNote: The approximate length of this media piece is 5 minutes. This resource can help you conduct an independent-sample t test from sample data in SPSS.