How to perform one way ANOVA for unequal number of samples. What changes need to be made while doing one way ANOVA with unequal sample sizes in GraphPad Prism when compared to equal number of sample sizes?
For example: four groups with different samples sizes as below
Group A: n=5; Group B: n=10; Group C: n=10; Group D: n=8
Thanking you in advance.
Regards
Eshvendar Reddy
you can perform proc GLM on SAS for unbalanced data..
Replace the Word Proc anova by proc glm.. others are same..then do not enter the data if it is missing.. just enter what you have.
it does not make any different. You can perform one way ANOVA with unequal sample sizes. Refer any good statistics books.
Dear Eshvendar
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 ).
In case your data met these assumptions, you can use Complete Randomized Design ( CRD ) with unequal replication ( observations ) by using calculator or by using SAS software ( or SPSS or other software ) , in case of calculator you can use the same procedure for equal replication with many changes you can observe in the attached pdf file on page 12 , and its application in SAS.
Good Luck
Just take the different sample size into consideration in your computation. A better method to do ANOVA is to use regression and coded (Dummy)variables. It is easier for you using SPSS or any other software.
Hello Eshvendar, nowadays, most of the software statistical packages deal with the issue of unequal sample sizes.
That only thing you have to do is to take the different sample size into consideration in your computation. A better method is to run one way ANOVA using regression and coded (Dummy)variables. It is easier for you using SPSS or any other software.
you can perform proc GLM on SAS for unbalanced data..
Replace the Word Proc anova by proc glm.. others are same..then do not enter the data if it is missing.. just enter what you have.
One-way ANOVA for unequal number of samples should run same as an equal number of samples ANOVA (using type 2 SS)
Read more here https://reneshbedre.com/blog/anova.html
Dear Dr. Eshvendar Reddy Kasala, the vast majority of statistical programs can automatically handle the issue of unequal sample size. Thus, the short answer is just to run ANOVA as usual and do not worry about unequal sample sizes.
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