About Vivian Expertise I can answer questions on probability, distributions, statistical inference, statistical estimation, hypothesis testing, analysis of categorical data, linear regression, generalized linear regression, ANOVA, and linear mixed models. I cannot answer questions on stochastic processes.
Experience I have worked as a research assistant at the University of Michigan, Ann Arbor for two years.
Organizations American Statistical Association
Education/Credentials University of Michigan, Ann Arbor
Master of Science
Question I am having problems in analyzing a set of data. I have found that, at times, a
one-way ANOVA yields a significant p-value for the test, but post-hoc tests
don't reveal any specific differences (all post-hoc tests are non-significant). I
was under the impression that this situation is not supposed to happen. Is it
possible to have this result? Or is this problem most likely based on how my
data has been entered into the statistics program?
Answer If a one-way ANOVA yields a significant p-value, it means that at least one comparison between means that is significant. I do not know which post-hoc tests are used in your program. Usually the post-hoc tests used in software will give at least one significant result. But it is really dependent on your post-hoc tests. Are your post-hoc tests too conservative?
Please let me know the reason if you find it finally. Also, please feel free to discuss it with me. The selection of post-hoc test is not a small topic.
