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Technical Report

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Water research, data analysis, algae


This report presents and discusses the basic statistical models and methods which are useful to researchers in the field of water resources research, as well as in other fields. These models and methods are presented from the standpoint of type (parametric and nonparametric - or distribution free) and purpose (e.g., simultaneous comparison of several means, comparison of two or more variances, establishment of a difference between two means with a specified confidence, etc.). The material is presented with emphasis primarily upon methodology, including the necessary assumptions upon which each model is based. No derivations or proofs are given, since these are found in numerous textbooks on statistics readily accessible to the reader. Emphasis is also placed upon the need for the researcher to determine before obtaining data the type of statistical model and analysis required, so that he can use that model or method which is most powerful, and so that he will have the proper data to permit the most efficient analysis. Failure to carry out such preliminary planning relevant to the selection and application of a statistical model will almost always result in either a lack of sufficient relevant data or in the gathering of extraneous data, either of which is unnecessarily costly. Each method is illustrated by an example, together with an interpretation of the result.

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