Experimental Designs in Statistics
(The Principles of Experimental Designs in Research Methodology)
What is a statistical experiment?
Ø An experiment is a plan for the collection and analysis of data.
Ø “It is a controlled act through which data are collected according to some pre-determined objective”.
Ø The observations obtained from a carefully planned and well-designed experiment in advance only gives valid inferences.
Ø An experimental design which gives the smallest error is supposed to be the best design for a particular type of investigation.
Experimental unit (Experimental Plot):
Ø The smallest division of the experimental material to which we apply the treatment and can make the observation on it is called experimental unit or experimental plot
Ø Treatments are the characteristics which are to be investigated through an experiment.
Ø The treatments are the objects of comparisons in an experiment.
Ø Example: effects of different fertilizers, the yield of different varieties of a crop, disease resistance of different cultivars etc.