Why is it necessary to run a post hoc test after you run a simple ANOVA? Group of answer choices The F-statistic and p-value tells us whether or not there is a difference between means, but it does not tell us where the difference lies. The post hoc test tells us where the difference lies. Post hoc tests are used when the data is not normally distributed Post hoc tests are used when the differences between means is too small to detect with a simple ANOVA Post hoc tests are used when the sample size is small
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Describe the general rationale behind using post hoc tests (i.e., when they are used and why). One of the advantages of using an ANOVA (compared to using t-tests) is also a disadvantage—using an ANOVA makes it necessary to use post hoc tests if there is a significant main effect. We use a post hoc test because there is one specific advantage in using an ANOVA. Explain why using an ANOVA naturally leads to the need to have post hoc tests (hint: consider what you are examining when you conduct a post hoc analysis). Conducting a post hoc test is similar to conducting multiple t-tests. As a result, it would seem natural to want to bypass the ANOVA and just use repeated t-tests. Explain why this approach is not necessarily a good idea and why an ANOVA followed by a post hoc analysis is beneficial. Describe an experimental hypothesis and explain which post hoc test you would use if you find a significant overall effect. Include in your explanation the pros and cons of each test in making your decision.
Adi S.
Consider the different post hoc tests discussed in the readings and respond to the following: Describe the general rationale behind using post hoc tests (i.e. when they are used and why). One of the advantages of using an ANOVA (compared to using t-tests) is also a disadvantage - using an ANOVA makes it necessary to use post hoc tests if there is a significant main effect. We use post hoc tests because there is one specific advantage of using an ANOVA. Explain why using an ANOVA naturally leads to the need to have post hoc tests (hint: consider what you are examining when you conduct post hoc analysis). Conducting post hoc tests is similar to conducting multiple t-tests. It would seem natural to want to bypass the ANOVA and just use repeated t-tests. Explain why this approach is not necessarily a good idea and why an ANOVA followed by post hoc analysis is beneficial. Describe an experimental hypothesis and explain which post hoc test you would use if you find a significant overall effect. Include in your explanation the pros and cons of each test in making your decision.
For Exercises 9 through $13,$ do a complete one-way ANOVA. If the null hypothesis is rejected, use either the Scheffé or Tukey test to see if there is a significant difference in the pairs of means. Assume all assumptions are met. Emergency Room Visits Fractures accounted for $2.4 \%$ of all U.S. emergency room visits for a total of $389,000$ visits for a recent year. A random sample of weekly ER visits is recorded for three hospitals in a large metropolitan area during the summer months. At $\alpha=0.05,$ is there sufficient evidence to conclude a difference in means? (TABLE NOT COPY)
Analysis of Variance
The Scheffe Test and the Tukey Test
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
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