Organophosphate (OP) compounds are used as pesticides. However, it is important to study their effect on species that are exposed to them. In the laboratory study Some Effects of Organophosphate Pesticides on Wildlife Species, by the Department of Fisheries and Wildlife at Virginia Tech, an experiment was conducted in which different dosages of a particular OP pesticide were administered to 5 groups of 5 mice (Peromyscus leucopus). The 25 mice were females of similar age and condition. One group received no chemical. The basic response y was a measure of activity in the brain. It was postulated that brain activity would decrease with an increase in OP dosage. Use the provided data to do the following.
(a) Find the least squares estimates of β0 and β1 using the model

Y_i = β₀ + β₁x_i + ϵ_i,    i = 1, 2, . . . , 25.

(b) Construct an analysis-of-variance table in which the lack of fit and pure error have been separated. Determine if the lack of fit is significant at the 0.05 level. Interpret the results.

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Dose, x (mg/kg body weight) 0.0 Activity, y (moles/liter/min) 10.9 Animal 0.0 10.6 3 0.0 10.8 4 0.0 9.8 0.0 9.0 2.3 11.0 11.3 2.3 2.3 9.9 9.2 2.3 10 2.3 10.1 11 4.6 10.6 12 4.6 4.6 10.4 13 8.8 14 4.6 11.1 15 4.6 8.4 9.7 16 9.2 17 9.2 7.8 18 9.2 9.0 9.2 19 8.2 2.3 20 9.2 21 18.4 2.9 18.4 22 23 2.2 18.4 18.4 3.4 5.4 24 25 18.4 8.2