6.4 A pharmaceutical company conducts an experiment to compare 5 drugs. 30 animals are available for the trial. Each drug is injected into 6 randomly selected animals. All the animals are very similar. After an appropriate period of time 2 blood samples are taken from each animal and duplicate analyses are made for each blood sample. The reading from each analysis represents the observation to be used for the statistical analysis of this experiment. (i) What kind of experimental design has been used? (ii) What feature does this design have which we have not encountered before? (iii) How many types of errors can you identify for this design? Give their names. (iv) Write out an appropriate model for this design. (v) Based upon this model, outline the ANOVA table, giving sources of varia- tion and degrees of freedom. (vi) Using the ANOVA table. indicate how you would test the hypothesis that there are no differences among the drugs.