A study of forced expiratory volumes of asthmatics was performed at three medica
ID: 3230438 • Letter: A
Question
A study of forced expiratory volumes of asthmatics was performed at three medical centers, with the following results: Sigma^5_i=1 x_1i = 14.04 Sigma^5_i=1 x^2_1i = 41.0944 Sigma^5_i=1 x_2i = 14.47 Sigma^5_i=1 x^2_2i = 44.1519 Sigma^5_i=1 x_3i = 21.65 Sigma^5_i=1 x^2_3i = 94.8837 Test the hypothesis that there is no difference in expiratory volumes of asthmatics at the three centers: 1.1. What are the null and alternative hypotheses? 1.2. What is your conclusion? 1.3. If there is a significant difference among the means, which test would you use to determine which of the means are significantly different from each other? 1.4. Perform the test in 1.3, if called for.Explanation / Answer
(1.1) Ho: 1 = 2 = 3 versus Ha: At least one of the means is different from the other two
(1.2)
Since 0.0048 < 0.04, we reject Ho and conclude that at least one of the means is different from the other two
(1.3) We perform Tukey's simultaneous compaison test
(1.4)
Conclusion: Mean of Center 3 differs significantly from those of Center 1 and Center 2.
One factor ANOVA Mean n Std. Dev 2.808 5 0.6462 Center 1 2.894 5 0.7543 Center 2 4.330 5 0.5337 Center 3 3.344 15 0.9409 Total ANOVA table Source SS df MS F p-value Treatment 7.3100 2 3.65498 8.63 .0048 Error 5.0850 12 0.42375 Total 12.3950 14Related Questions
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