Statistics Homework for MathematicsExpert

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