Statistics Homework for MathematicsExpert
Running head: UNIT 3 1
Unit 3 Data Analysis and Application
PSY8501
Unit 3 Template
The following assignment reviews the concepts of power, effect size, alpha level, and sample size within the context of an independent samples t-test. Two variables are included in this analysis. “Gender” is a categorical variable designated as the independent variable (male = 1; female = 2). The case with a Gender code of 3 is ignored in this analysis. “HR1” is the dependent variable representing participant heart rate at baseline. The total sample size is N = 64. Output from G*Power and SPSS output are included where appropriate.
Reporting the t Test Results
This first question challenges our understanding of effect size, which is Cohen’s d. Conceptually, think of Cohen’s d as a signal to noise ratio:
Cohen’s d = signal/noise
Cohen’s d = M1 – M2 / s
Figure 1. Descriptive statistics of HR1 scores across levels of gender.
Figure 2. Levene test output.
Figure 3. SPSS output for the t test.
Cohen’s d effect size:
Post Hoc Power Analysis
Figure 4. Post Hoc Power Analysis output.
A Priori Power Analysis
Figure 5. A Priori Power Analysis with d = -.13.
Figure 6. A Priori Power Analysis with d = .50.
Conclusion:
References