Completely Randomized Block ANOVA
Now let’s modify the original fertilizer example: rather than select 18 random samples from my lawn, we are going to collect 3 random samples from 6 different lawns. Using the original data, the samples look as follows:
One concern in this scenario is that the variations in the lawns will account for some of the variation in the three fertilizers, which may interfere with our hypothesis test. We can control for this possibility by using a completely randomized block ANOVA, which is used in the previous table. The type of fertilizer is still the factor, and the lawns are called blocks.