Additional considerations about ANOVA

Before completing our discussions of ANOVA, there are several additional points that we would like to address, because these questions may have occurred to you as you have read the preceding descriptions of the use of ANOVA and multiple comparisons in this chapter. 

A one-way ANOVA containing three levels was used as the worked example in this section because a t test cannot address a design with more than two levels. However, the one-way ANOVA can certainly be used in situations involving only two levels. A reasonable question, therefore, is In situations involving only two levels, where the only possible comparison is between one level and the other, is there any advantage in using the one-way ANOVA instead of the t test  

The answer is no. In cases where there are only two levels, either test is applicable. The values obtained in the calculations of the respective tests will be different, but the tests will give precisely the same answer in terms of the degree of statistical significance obtained by the respective test statistic. That is, the t value and F value 

2 Only collect data that you intend to analyze 

A much more realistic scenario is one in which four doses are included in such a study because 

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