Contents
When should a factorial ANOVA test be used?
The factorial ANOVA should be used when the research question asks for the influence of two or more independent variables on one dependent variable.
What can I do with non-normal data?
Many practitioners suggest that if your data are not normal, you should do a nonparametric version of the test, which does not assume normality. From my experience, I would say that if you have non-normal data, you may look at the nonparametric version of the test you are interested in running.
Is an ANOVA a factorial design?
A factorial design is a type of experimental design, i.e. a plan how you create your data. An ANOVA is a type of statistical analysis that tests for the influence of variables or their interactions.
Can you use ANOVA to analyze a non-normal distribution?
If it looks like a normal distribution that has been pushed to one side, like the sulphate data above, you should try different data transformations and see if any of them make the histogram look more normal. If that doesn’t work, and the data still look severely non-normal, it’s probably still okay to analyze the data using an anova.
Are there any non parametric tests for ANOVA?
Just about every parametric statistical test has a non-parametric substitute, such as the Kruskal–Wallis test instead of a one-way anova, Wilcoxon signed-rank test instead of a paired t-test, and Spearman rank correlation instead of linear regression. These non-parametric tests do not assume that the data fit the normal distribution.
Can a regression be carried out on non-normal data?
It is a rather common misconception that regression and ANOVA can’t be carried out on non-normal data. The assumptions we make in ANOVA are: Residuals are approximately normal in their distribution. The residuals are independent – meaning the observed values are not correlated in some way.
How to perform one way ANOVA for unequal number of samples?
I have two groups, drug treated vs control, and obtained tissue and made measurements at 5 different time points. A 2-way ANOVA works for some of the variables which are normally distributed, however I’m not sure what test to use for the non-normally distributed ones. Samples size varies but ranges from 7-15 per group at each time point.