In many biological studies of water quality, a diversity index is calculated in 'bits per individual' by using Shannon's Approximation to Brillouin's Formula. Difficulties associated with such use of Shannon's Formula and its associated parameters are discussed. Recent research has indicated that diversity indexes can be improved if (a) biological sample collection and analysis are standardized prior to use for among various aquatic systems diversity indexes and their associated parameters, (b) the diversity index is measured in 'sits per individual' rather than the presently used unit of 'bits per individual,' and (c) the equation e=(H - H(min)/(H(max) - H(min)) is used to evaluate the uniformity of distribution of individuals among species in a sample where e equals relative evenness. Relative evenness, a ratio, is an expression in which Brillouin's and Shannon's Equations are not arbitrarily mixed. Values of diversity indexes using Brillouin and Shannon Formulas, both in bits and sits per individual, and relative evenness are given for 16 hypothetical samples.
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Indexes associated with information theory in water quality