Stat > Power and Sample Size > General Full Factorial Design > Design
Include terms in the model up through order
Select the highest-order interactions to include as terms in the model. If you have 1 replicate, select a number other than the maximum so that the calculations have enough degrees of freedom. Specifying the highest order is conservative, but you can specify a lower number if you plan to ignore higher-order interactions when you analyze the design. For example, in a 5-factor design with 2 replicates, you can include terms up through order 5. If you plan to study interactions between only 2 factors at a time, select 2.
Include blocks in model (design blocked on replicates)
Usually, you include blocks in the model if each replicate is a separate block. You can exclude blocks if you can collect all the replicates under homogenous conditions. You can also exclude blocks to ignore any block effect. For example, if you already analyzed the design and the block effect was not statistically significant or if you want to see the effect on the calculations when you ignore blocks. For more information on what a block is, go to What is a block?.