10. ANOVA 统计方法.pdfVIP

ANOVA ECS526 (ex) To find out whether a new serum will arrest leukemia, 9 mice, all with an advanced stage of the disease, are selected. 5 mice receive the treatment and 4 do not. Survival times, in years, from the time the experiment commenced are as follows: Treatment 2.1 5.3 1.4 4.6 0.9 No Treatment 1.9 0.5 2.8 3.1 At the 0.05 level of significance can the serum be said to be effective? Assume the two distributions to be normally distributed with equal variances. No Treatment Treatment 2.1 1.9 5.3 0.5 1.4 2.8 4.6 3.1 0.9 What do we do when we want to test if more than two means are equal? (ex) An investigation was conducted to determine the source of reduction in yield of a certain chemical product. It was known that the loss in yield occurred in the mother liquor, that is, the material removed at the filtration stage. It was felt that different blends of the original material may result in different yield reductions at the mother liquor stage. The following are results of the percent reduction for 3 batches at each of 4 preselected blends: Blend 1 2 3 4 25.6 25.2 20.8 31.6 24.3 28.6 26.7 29.8 27.9 24.7 22.2 34.3 Analysis of Variance (ANOVA) • ANOVA is a statist