ANOVA
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Abstract: Patients with advanced cancers of the stomach, bronchus, colon, ovary or breast were treated with ascorbate. The purpose of the study was to determine if the survival times differ with respect to the organ affected by the cancer. The data in the spreadsheet is the number of days individuals survived following treatment with ascorbate for 5 types of cancer.
Reference: Cameron, E. & Pauling, L. (1978) Supplemental ascorbate in the
supportive treatment of cancer: re-evaluation of prolongation of survival times
in terminal human cancer. Proceedings of the National Academy of Science USA,
75, 4538-4542.
Answer the question, did ascorbate affect survival time for the five types of cancers? Use alpha < 0.05 to answer this question.
1. Write the null hypothesis for the comparison in words (not in equation form).
2. Write the alternative hypothesis for the comparison in words.
3. Using this web site, http://vassun.vassar.edu/~lowry/VassarStats.html, follow the link to ANOVA in the left menu and calculate the answer using the One-Way ANOVA and Tukey’s post-hoc analysis. Include the ANOVA Summary Table in your solution.
4. Based upon the ANOVA results, what do you conclude? Justify your answer (Hint, a sentence like the following would be a strong answer to this question:
F (df bg, df wg) = , p = ) means that we _________ the null hypothesis. Further analysis with the Tukey test indicated that ______________________________.
5. Create a column graph for the five groups and include the error bars (95% confidence intervals) on each column bar.