Potential Limitations of ANOVA TestingDate: 11/13/2005 at 14:59:06 From: Cathy Subject: anova statistics What is the DISADVANTAGE of the information reported by an ANOVA? I can find all sorts of information about the results and use of ANOVA, but nothing on the disadvantage of the information the test reports. According to my text book reference sources, it appears that there are few (if any) disadvantages. Date: 11/14/2005 at 11:42:25 From: Doctor Minter Subject: Re: anova statistics Hi Cathy! The most distinct disadvantage to the analysis of variance (ANOVA) method is that it requires two assumptions to be made: 1. All population means from each data group must be (roughly) equal. 2. All variances from each data group must be (roughly) equal. Obviously, we rarely have this luxury in real-world applications. There is light at the end of the tunnel, however, in the form of something called the Kruskal-Wallis Test, a non-parametric method that will allow us to obtain a strong base to accept or reject the null hypothesis if these assumptions cannot be made. If the assumptions are valid, however, ANOVA is unequivocally a powerful tool. I hope this has shed some light on this method of statistics. Please feel free to write again if you need further assistance, or if you have any other questions. Thanks for using Dr. Math! - Doctor Minter, The Math Forum http://mathforum.org/dr.math/ |
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