Statistical Power and Sample Size Analysis Custom Paper

Researchers have long lamented that many published studies lack statistical power. What if you conducted a study and calculated in advance that the sample size you need would give you only 50% power? This means that your study has a 50-50 chance of showing an effect if it exists. You could save a lot of time and money and just flip a coin!
This week, you will learn how to calculate appropriate sample sizes to ensure that the more sophisticated designs you are learning in this course have adequate power.
Learning Outcomes
By the end of this week, you will be able to:
• Calculate required sample size for test of sufficient power using G*Power
• Propose the sample strategy for getting a sample of the requisite size
Required Resources
This page contains the Learning Resources for this week. Be sure to scroll down the page to see all of this week’s assigned Learning Resources. To access select media resources, please use the media player below.
• Course Text: Research Methods in the Social Sciences
o Chapter 8, "Sampling and Sample Designs"

This chapter provides an overview of population, sample designs, sample size, and nonsampling errors.

• Website: Trochim, W.M.K. (2006). Statistical power. Retrieved from

This website provides an overview of the components of statistical power, including sample size, effect size, alpha level, and power.

• Website: Buchner, A., Faul, F., & Erdfelder, E. (n.d.) G*Power. Retrieved January 29, 2010, from

The G*Power website explains the purpose and features of G*Power and allows users to download the program.

• Media:
o "Article Critique " (6:54)

Click here to download a transcript of this video segment.

Dr. Gary Burkholder explains the benefits of critiquing peer-reviewed articles and provides guidelines to assist you in your article critique. To view this video program, use the media player located at the top of this page.

o G*Power Software: A Practical Demonstration (Adobe Captivate)

Dr. Carl Sheperis explains the concept of statistical power and demonstrates a power calcuation using G*Power. This Flash-based demonstration will open in a new window.

Click here to download a transcript of this demonstration.

o Understanding Power and Effect Size: A Practical Overview (Adobe Captivate)

Dr. Carl Sheperis explains the concept of statistical power. This Flash-based demonstration will open in a new window.

Click here to download a transcript of this demonstration.
Research Toolkit
Research Design
• Website: Web Center for Social Research Methods

This website is for people involved in applied social research and evaluation. You will find several resources and links to other locations on the Web that deal in applied social research methods.

• Website: Cengage Research Methods Workshops
https://www.wadsworth.com/psychology_d/templates/student_resources/workshops/resch_wrk.html

This website offers many useful workshop topics such as experimental methods, reliability and validity, surveys, sampling methods, ethical issues, and evaluating published research.

Discussion – Week 10
Sampling Strategy
In this week’s Discussion and Application assignments, you will continue to work on your Final Project. In this Discussion, you will describe your sampling strategy for your chosen research proposal.
To prepare for this Discussion:
• Review Chapter 8 in the Frankfort-Nachmias and Nachmias book and the statistical power discussion on the Research Methods Knowledge Base website in this week’s Learning Resources.
• Consider the quantitative research plan you are developing for your Final Project and your research questions, hypotheses, variables, and analysis. What kind of power would be necessary for your research problem to be able to tell you what you would like to learn? What kind of sampling strategy would you recommend for your plan? What is your rationale for this choice?