The data listed in the following relate to a study by Reiter

The data listed in the following relate to a study by Reiter and others(1981) concerning the effects of injecting triethyl-tin(TET) into rats once at age 5 days. the animals were injected with 0, 3, or 6 mg per kilogram of body weight. the response was the log of the activity count for 1 hour, recorded at 21 days of age. the rat was left to move about freely in a figure 8 maze. analysis of other studies with this type of activity count confirms that log counts should yield Gaussian errors if the model is correct.

a. tabulate the dosage x sex cell sample sizes. explain why this might be called a nearly orthogonal design.

b. using the accompanying SAS computer output, conduct a two-way ANOVA with SEX and DOSAGE as factors.( First provide the F statistics values and P-values in the accompanying ANOVA table).

c. Using a=.05, report your conclusions based on the ANOVA.

Solution

the table values at 5% level of significance with F(2,53)=3.172 and F(1,53)=4.023, so Fcal<Ftab in case of dosage,sex and interaction effects also. so we accept null hypothesis. Therefore, there is no significant differences of means among dosages ,sex and interaction.