Designs Based on Randomness: Mersenne Twister Design

 

The MT Design was generated using R and MS Excel. R is an open access software, so it does not have a cost. This is a well-known statistical software characterized by its computational capacity. The Microsoft Office suite that includes Excel, in its version "Office home and student 2013" has a cost of $139.99, while the "Office Home and Business 2013" has a cost of $219.99 (MS Office Store, 2014). Freely-distributed electronic spreadsheets, such as those included in LibreOffice and OpenOffice, could feasibly be used instead in further applications.

       For this design the MT algorithm was coded in R. The initial step is setting the seed to then generate vectors of magnitude v, where v represents the number of necessary regression coefficients to fit a full quadratic model plus one. These vectors were copied into Excel to be translated into practical levels. For this design k vectors were generated, where k represents the number of variables to be investigated. For each vector, if is necessary to establish a new seed. The computer time to generate each vector is negligible, as it takes only a few seconds. The process of copying and adjusting each vector in Excel, with the translation to the selected levels, takes approximately 0.5 minutes. The expression of the total generation time is 0.5n. For 50 variables for example, the design generation time was calculated as 0.5(50) = 25 minutes approximately. Using this approximation, the total cost associated to the generation of this design is $164.99.