Designs Based on Randomness: Random Design

 

The generation of this design is, as its name indicates, completely random. It is not possible to control the design’s statistical properties. In this method it is necessary to create a matrix with the levels of the variables’ to be investigated on the design and the probability for each level. The number of experimental runs is established by the user.

        This design was generated in this work using Minitab following a uniform discrete distribution. The perpetual license of this software has a cost of $1,495 without upgrades versions (Minitab Inc. 2014). The computing time for the generation of this design, in 50 variables, can be considered negligible because it only takes a few seconds. Therefore, the total cost associated to the generation of the random design is $1,495. It is important to note that it is possible to reduce the software cost to 0 with the use of freely-distributed electronic spreadsheets, such as those included in LibreOffice and OpenOffice.