Randomized block design

I was informed about Randomized Block Design (RBD) in SPSS research but I have no idea about it. Can anyone please explain it in details with an example?

1 comment to Randomized block design

  • I am trying to answer about Randomized Block Design (RBD) which is often used specially in health SPSS research. Suppose, a health research agency (HRA) is appropriate only for experiments having homogeneous experimental units and a small number of treatments. In experiments having heterogeneous experimental units and large number of treatments, randomized block design especially involving blocks as local control measure is used to control the heterogeneity and variability among the experimental units.

    Common sense if several varieties of a crop are shown on plots containing marked difference in soil fertility, then the difference in yields will arise both due to variety difference and soil fertility differences and the effects of these two factors cannot be separated at all. Here we say that variety differences and soil fertility differences are completely mixed up or confounded and so no valid conclusion can be reached.

    In an industrial experiment conducted in a HRA, if the production from one machine turns out to be relatively large, we cannot say how much of this increased production is due to the effectiveness of machine and how much is due to the efficiency of the particular group of workmen operative the machine. Here we assert that the effects due to machines and the effects due to machine men are completely confounded. Moreover, infested error variation destroys the sensitivity of detecting treatment differences.

    A randomized block design (RBD) in which the whole set of experimental units are arranged in several blocks which are internally homogeneous and externally heterogeneous and then the selected treatments are randomly allocated to the experimental units within each block such that each treatment occurs once or same number of times, in each block. So, in SPSS research, RBD is mostly important regarding K treatments. This is just an example I placed here. If you need to more about it, please specify the question.