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Unformatted text preview: /20 QUESTION #3 /2 a) H : The average chicken weight is the same for all three levels of the drug in the chick feed. OR μ 1 = μ 2 = μ 3 where μ i represents the population average chicken weight for the ith dose. OR τ i = 0 where τ i represents the effect (difference between trt mean and overall mean) of the ith dose. H a : The average chicken weight differs for at least one level of the drug in the chick feed. OR Not a i are equal. OR not all τ i = 0. NOTE: ANOVA tests a general alternative hypothesis – it is not testing for an increas compared to the control. That will have to be done using contrasts. /2 b) Clearly from the scatterplot, supplementing the chick food with the drug does appear to increase the a weight at maturity. There appears to be a substantial difference between the control (no drug) and th whereas, there is a lesser increase between the low and the high dose. Note in the plot high dose ap dose – a flaw with the plotting routine. Page 1 of 7 From this plot we can see that the profiles for the different blocks are not parallel but cross each other is either no difference among blocks  indicating that blocking was not an effective tool  or there is a b treatment interaction  which will inflate the error term making it harder to detect differences among tre ANOVA below indicates that blocks are not significant while treatments are – so probably blocking wa effective. However our analysis must be a RCB since that was how the study was designed – reducin 1way ANOVA is not appropriate, after the fact....
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 Winter '09
 OHaraHines
 Normal Distribution, Multiple comparisons, Dunnett, average chicken weight

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