Contents
Can you compare unequal sample sizes?
Some tests are set up specifically to deal with the problem of unequal sample sizes and unequal variances: Dunnett’s T3 or Dunnett’s C can be used for pairwise comparisons. Use T3 for small samples, and C for larger samples. Welch’s Test for Unequal Variances is a modified Student’s t-test.
Can you do ANOVA with unequal sample sizes?
You can perform one way ANOVA with unequal sample sizes. You must consider the assumptions of Normality, equality of variance and independence ( that mentioned by Saigopal ) before using ANOVA and in a case of not correct assumption then you must use non-parametric test ( Kruskal-Wallis test ).
Why is a small sample size a limitation?
A sample size that is too small reduces the power of the study and increases the margin of error, which can render the study meaningless. Researchers may be compelled to limit the sampling size for economic and other reasons.
How to calculate Sample Size for a study?
Bearing this point in mind, there are different formulas to calculate sample size.2,3These formulas comprise several aspects which are listed below. Most sample size calculators available on the web have limited validity because they use a single formula – which is usually not divulged – to generate sample sizes for the studies.
How can I compare groups with unequal sample sizes?
I have two datasets containing Z-score data. However both of them are of highly different sizes, i.e one has 500 samples while the other has 4. I want to determine if the differences between the samples is statistically significant.
What’s the difference between 500 and 4 samples?
However both of them are of highly different sizes, i.e one has 500 samples while the other has 4. I want to determine if the differences between the samples is statistically significant. I thought of using an unpaired t-test, but I am not sure if the difference in sample sizes would invalidate the method.
Is it good to have a small sample size?
Therefore, ideally, samples should not be small and, contrary to what one might think, should not be excessive. The aim of this paper is to discuss in clinical language the main implications of the sample size when interpreting a study. Keywords: Sample calculation, Sample size, Clinical trial, Methodology, Scientific evidence