Biostatistics Study Materials

Principles of Experimental Designs in Statistics – Replication, Randomization & Local Control

Experimental Research Design

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.

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