We need extra runs to design two-level factorial experiments in blocks of size two to estimate all the available effects, as is possible in experiments without blocking. The number of runs suggested is (n − p)2n−p for 2n−p fractional factorial experiments. In designing such an experiment, two issues need to be considered. First, the precision of estimates is usually different because different ...

using surface analysis, simultaneous effects of temperature (260-380ºc) and ethanol concentration (0-1%) on dimethyl ether (dme) selectivity, yields of hydrocarbon and dme, and methanol conversion were investigated in methanol dehydration reaction over γ-al2o3 catalyst. methanol conversion and yield of hydrocarbon/dme were found to be significantly affected by temperature and the temperature-et...