Question

The following data represent the results from an independent-measures experiment comparing three treatment conditions. Use a spreadsheet to conduct an analysis of variance with a = whether these data are sufficient to conclude that there are significant differences between the 0.05 to determine treatments. Treatment A Treatment B Treatment 19 22 24 20 20 25 20 19 26 20 21 22 21 23 28 F-ratio = p-value - Conclusion: There is a significant difference between treatments These data do not provide evidence of a difference between the treatments The results obtained above were primarily due to the mean for the third treatment being noticeably different from the other two sample means. For the following data, the scores are the same as above except that the difference between treatments was reduced by moving the third treatment closer to the other two samples. In particular, 3 points have been subtracted from each score in the third sample. Before you begin the calculation, predict how the changes in the data should influence the outcome of the analysis. That is, how will the F-ratio for these data compare with the F-ratio from above? Treatment A Treatment B Treatment 19 22 21 20 20 22 20 23 20 21 19 21 23 25 19 F-ratio = p-value - Conclusion: These data do not provide evidence of a difference between the treatments There is a significant difference between treatments

Answer 1

А B с Anova: Single Factor 19 22 24 20 20 25 20 19 26 SUMMARY Groups А B 20 21 22 Count 5 5 Sum 100 105 125 Average Variance 20 0.5 21 2.5 25 5 21 23 28 с 5 SS df MS ANOVA Source of Variation Between Groups Within Groups Total F P-value F crit 13.125 0.000953 3.885294 70 32 102 2 35 12 2.666667 14 ## Answer: F-ratio = 13.125 p-value = 0.001 There is a significant differnce between tratment means

А B с Anova: Single Factor 19 22 21 20 20 22 SUMMARY 20 19 23 Groups Average 20 20 21 19 A Count Sum 5 100 5 105 5 110 Variance 0.5 2.5 21 23 25 B 21 с 22 5 SS ANOVA Source of Variation Between Groups within Groups Total F P-value 1.875 0.195615889 Fcrit 3.885293835 10 df MS 2 5 12 2.666666667 14 32 42 ## Answer: F-ratio = 1.875 p-value = 0.1956 these data does not provide evidence of differnce between tratment means