On Demand Tutorial: Calculating Power and Sample Size

Don’t let sample size calculations hold you back.


Working on a grant? Creating your dissertation proposal?

Committed to generating research results that will be taken seriously for publication?

Want to satisfy the Institutional Review Board?

Then you MUST consider sample size BEFORE you start your study. But it’s likely that your past statistics classes didn’t teach you what you need to know about calculating sample size and power estimates.

Yes, mainstream statistical software makes it easy for you to calculate power after the fact, but that isn’t going to do you much good (and it’s dubious at best).

The solution:

Calculating Power and Sample Size

with G*Power and StudySize

A 4-Hour Online Tutorial




“This course is a good refresher for those who have covered [the topic] before and a great introduction for those with little or no knowledge of power and sample size calculations.”

— Jacqui Wilson, Senior Research Assistant
The University of Newcastle, Australia
Calculating Power and Sample Size Student



Karen Grace-MartinI’m Karen Grace Martin, your instructor for Calculating Power and Sample Size.

My goal is that by the end of the tutorial, you will understand the theory and logic behind power and sample sizes and be able to confidently undertake the calculations so you can get started on your research project.

In this four-hour online tutorial, we’ll start at the beginning: with a review of what power means and how it relates to statistical tests, effect sizes, standard deviations, and sample size.

You’ll learn how to calculate simple sample estimates using two specialized software programs: G*Power and StudySize.

You’ll be prepared to undertake your own power and sample size calculations with confidence.



Who Is This Tutorial For?


This tutorial is for you if:

  • You need to calculate sample size estimates for grant proposals or dissertation proposals
  • You want to confirm that a research study is worth doing… before you start
  • You’ve learned the basics of power and sample size, but you never really “got” it and now want to understand how to use these calculations in real research situations (or in anything harder than a t-test)
  • You have access to a statistical consultant who can help you calculate sample sizes, but you need to understand what information goes into those calculations (and how to get it)



How Does It Work?


This course is a four-hour online tutorial.

The tutorial and accompanying materials are already available for you to access on your private tutorial website. Log in at any time from any internet-enabled computer, phone, or tablet… all from your own home or office.

In the tutorial videos, the instructor will present concepts and explain the meaning of the techniques, then demonstrate how to implement those techniques in G*Power and StudySize software using different statistical examples.



As a participant in the Calculating Power and Sample Size tutorial, you’ll have access to a participant-only website, your tutorial “hub.” That’s where you’ll access all tutorial resources and material, including:

  • A set of streaming training videos.

    Watch (and re-watch) these videos on YOUR schedule, as many times as you like, at the speed you desire.

    These videos explain the concepts and steps as well as step-by-step demonstrations for how to implement sample size calculations in two software programs.

  • Supplemental PDF handouts.

    You’ll have access to the presentation slides, handy checklists, and worksheets to help you set up your next power calculation. You can download, print out, and take notes as you follow along.

  • A place to submit written questions.

    Got a question as you’re reviewing the video recording or your notes? Just submit a question in the tutorial website. We’ll answer it right there.

  • Bonus videos.

    To enhance your understanding of where power calculations fit into the data analysis process, we’ve included the following bonus video webinars:

The 13 Steps to Performing Any Statistical Model (60-minute video presentation)
The First 3 Steps to Statistical Modeling: How to Clarify the Research Question, the Design, and the Variables (60-minute video presentation)
Effect Size Statistics – An Overview (90-minute video presentation)
Small Sample Statistics (90-minute video presentation)
Confidence Intervals (90-minute video presentation)

You’ll have access to this site and all the related materials and resources for ONE FULL YEAR. That means you can re-watch videos, access resources, and ask additional questions during that 12-month period.



“Karen is a fantastically knowledgeable and patient person. There are no wrong or stupid questions when working with her, and everyone is encouraged to participate. As well, really helpful for me was the option to go through all the materials at the time that worked best for me and to access and go through the same material over and over again if needed. Fantastic workshop!”

— Danijela Gasevic, Simon Fraser University
Calculating Power and Sample Size Student


What’s Covered?


Our goal is for you to be able to calculate simple sample estimates, on your own, using G*Power or StudySize.

After participating in this tutorial, you’ll:

  • Have an intuitive understanding of power, effect sizes, hypothesis tests, and Type I and Type II errors
  • Comprehend how power, effect size, and standard deviation relate to sample size in a variety of statistical tests (t-test, ANOVAs, and linear and logistic regressions)
  • Know how to apply the steps to any problem because you’ll understand the logic behind sample size calculations so you can apply them independently
  • Be familiar with the five pieces of information you MUST have to perform any sample size calculation (as well as where to get them, and the steps for using them)
  • Understand your options for increasing power in a study
  • Understand why effect sizes are important to power and sample size calculations, and the best way to measure them in a variety of tests
  • Grasp why it’s NOT useful to calculate power after performing a study
  • Know where sample size calculations fit into the 13 steps of data analysis
  • Understand how to perform complex calculations (using StudySize 3.0 and G*Power software programs)
  • Be familiar with examples of prospective sample size estimates for a two sample t-test, as well as ANOVA and multiple and logistic regression analysis (in all three software packages)





The Details


The basic tutorial materials are available immediately via the tutorial website.

Also, you have access to all the class materials for a full 12 months from your enrollment date.


Full Tutorial Investment: $197



Your Tutorial from The Analysis Factor Includes:

  • 1 year of access to the tutorial website
  • 4 hours of videos covering the concepts, steps, and software demos
  • All the exercises and handouts you’ll need
  • The opportunity to submit questions to be answered on the website



“Nice to have access to Karen, et al. for a whole year when I go back to review this material.”

— Joanne Basta, Manager
Research & Evaluation Unit, Pima County Juvenile Court Center
Calculating Power and Sample Size Student



About Your Instructor


As president and founder of The Analysis Factor, I’ve been supporting researchers like you through their statistical planning, analysis, and interpretation since 1997.

With masters degrees in both applied statistics and social psychology, I’ve been honored over the past 15 years to work with everyone from undergrad honors students to Cornell professors, and from non-profit evaluators to corporate data analysts.

After seeing so many smart people get nervous, uncertain, and downright phobic about analyzing their data, I made it my mission to remove the barrier between research and statistical analysis.

I want to banish the theoretical jargon that makes eyes glaze over and instead explain statistical terminology in plain English.

My goal is to help you improve your statistical literacy so you can bring your important research results into the light with confidence.






So what kind of background in statistics do you need?

Our tutorials and workshops are for researchers, not statisticians.

That being said, you’ll get the most from this tutorial if you have a MINIMUM one statistics class, including some experience in data analysis.

An additional word about software packages:
You do NOT need prior experience with any specific statistical software. During the tutorial, we will be using two software packages:

  • G*Power*
  • StudySize 3.0**

*G*Power is a free downloadable application.

*A free 1-week trial download of Studysize 3.0 is available through our tutorial website. Download it right before you start so you can test it during your tutorial time and ask any questions you might have. After your free trial expires, it’s inexpensive to purchase. It has many options that G*Power doesn’t.

If you have questions about whether you’re ready for this tutorial, just email us. We’ll give you our honest opinion. We want you to succeed!



“Karen has a gift for explaining and teaching applied statistics. I really appreciate her patient, pleasant, down-to-earth manner. My previous statistics professors were knowledgeable, but un-engaging, and not easy to understand. I wish I would have had a teacher like Karen in my grad program.”

— Joanne Basta, Manager
Research & Evaluation Unit, Pima County Juvenile Court Center
Calculating Power and Sample Size Student


Your Satisfaction Is Guaranteed

As with all our programs, your satisfaction is guaranteed. If you participate fully in this tutorial – read, and try out everything included – and find you are not satisfied for any reason, we will give you a full refund, no questions asked. Just notify us within 90 days of purchasing the program.



Q. Will I be able to keep up with the tutorial material?

If you meet the prerequisites listed above, you’ll be prepared to understand the tutorial materials. BUT… we also suggest setting aside some time (2-4 hours) to re-run class examples and watch the bonus videos. Remember — you also have 12 months to revisit the material! It’s completely on YOUR schedule.

You know how this goes: The more time you put in, the deeper your understanding.

Q: Things are very busy at work right now, and I’m afraid I won’t have time to keep up. How much time will this really take?

A: We’ve worked really hard to make sure people can keep up with the tutorial in the midst of their normal work life. And with on-demand access, you’re all set to deal with unexpected deadlines or “life” emergencies.

The core videos total approximately 4 hours. If you have a crazy hectic month ahead, you can fit watching the materials into your schedule. You can also submit your questions in writing through the tutorial website.

One reminder: You have access to the tutorial website, all materials, and a place to ask questions for a year. So if you get behind, you aren’t missing out. You can catch up on your schedule.

Q: I teach/work/sleep during this time/live outside the U.S. and cannot attend at specific times. Is there any way to register and access these sessions later?

A: Yes! That’s the beauty of our on-demand tutorials. We have participants from many time zones with many different work schedules. In order to support our diverse student base, all tutorial sessions are pre-recorded and available immediately.

Q: I’m outside the U.S. Can I still participate?

A: Yes. We have participants in our tutorials and workshops from many different countries.

Q: Can I pay with PayPal?

A: Yes. When you check out, you can pay directly using our system or with PayPal.

Q: This really isn’t a good time for me. Will you be offering this tutorial again soon?

A. This tutorial (and several others!) are available year-round. You can sign up now and get access to all the course materials (trainings, support, exercises, the option to ask questions, as well as any additional bonuses). I would suggest registering now. You’ll get all the materials to download and review at your convenience, and you can access them for free any time in the next 12 months.

Registering now will give you complete access to the website and all materials for one year. Plus, ongoing support is included through access to the tutorial website for a full year.

Q. What software do you support for this class?

A: You do NOT need prior experience with any specific statistical software. During the tutorial, we will be using two software packages:

  • G*Power (a free downloadable software)
  • StudySize 3.0

Q: Are you covering sample size estimates for mixed models?

A: No. This tutorial is entry-level and is limited to the designs that G*Power and StudySize 3.0 can handle. Sample size calculations for mixed models are very complicated and require different, specialized software. Everything we talk about here applies to mixed models and the steps are the same, but we’re not going to go into the specific, extra info that you need in those situations. We are including examples of:

  • Independent and Paired T-test
  • Correlations
  • One-Way ANOVA
  • Intra-Class Correlations for Reliability
  • McNemar, Chi-Square, and Logistic Regression
  • Multiple Regression

Have additional questions? We’re here to help! Just email us at support@analysisfactor.com.