# Sample Size Tutorial

Sample size is a critical part of any quantitative research study.

My Statistical Data Analysis tutorial page provides a good explanation of the basic principles of probability and statistical inference. If you understand those concepts, you will understand why sample size is so important to the effectiveness of your study.

In very basic terms, the larger your sample size, the more likely you will be
able to find statistically significant results.

### Sample Size Justification

Since sample size is so important in making statistical inferences, your
committee naturally wants to be sure that your dissertation research uses an
adequate sample size to effectively address your research questions. That is why
you should include a "sample size justification" section in your
Methods Chapter.

Power Analysis is a family of statistical procedures which are used to justify the
appropriate sample size for testing a given statistical hypothesis.

### Sample Size Calculation

Sample size
calculation refers to using power analysis to determine an appropriate sample
size for testing your research hypotheses

.

### Sample Size and Statistical Power

In basic terms, "Statistical Power" is the likelihood of achieving a
statistically significant result if your research hypothesis is actually true.
In other words, if the null hypothesis is false, what is the probability that
your "sample" will produce statistically significant results at the p < 0.05 level of significance? If the
likelihood is good (e.g., at least 80% chance), for an acceptable "effect size", then your
sample size would be considered adequate (i.e. statistically powerful).

See my Power Analysis Tutorial for more
information.

### Get the Statistics Help you need

When I help you with the statistical considerations for your
dissertation proposal, I will
perform a power analysis to justify your sample size and I will determine which
statistical methods are appropriate for your
data analysis section. I also provide readily available
statistics help to make sure that you
fully understand all of the statistics that I used for your research.

Simply contact me by phone or email to get started.

Steve Creech

630-936-4771 | Steve@StatisticallySignificantConsulting.com

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