(Solution) - In a pharmacological study 12 rats were randomly allocated to -(2025 Original AI-Free Solution)

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In a pharmacological study, 12 rats were randomly allocated to receive an injection of amphetamine at one of two dosage levels or an injection of saline. Shown in the table is the water consumption of each animal (ml water per kg body weight) during the 24 hours following injection.39

(a) Calculate the regression line of water consumption on dose of amphetamine, and calculate the residual standard deviation.
(b) Construct a scatterplot of water consumption against dose.
(c) Draw the regression line on the scatterplot.
(d) Use linear regression to test the hypothesis that amphetamine has no effect on water consumption against the alternative that amphetamine tends to reduce water consumption. (Use a = 0.05.)
(e) Use analysis of variance to test the hypothesis that amphetamine has no effect on water consumption. (Use a = 0.05.) Compare with the result of part (d).
(f) What conditions are necessary for the validity of the test in part (d) but not for the test in part (e)?
(g) Calculate the pooled standard deviation from the ANOVA, and compare it with the residual standard deviation calculated in part (a).