probstats

# Probstats - A population is a collection of units of interest to us a variable would be a characteristic which could have different values for

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A population is a collection of units of interest to us, a variable would be a characteristic which could have different values for different units Categorical or qualitative data—when the variable has no numeric content Numerical or quantitative data—when the variable has numeric content. Subtypes of numerical data: a. discrete numeric variable—when the variable can assume only isolated possible values—usually counts b. continuous numeric variable—when the possible value of the variable fill out a whole interval—for example physical measurements Confounding variables may exist. A confounding variable is a hidden variable which is related to both of two variables which therefore turn out to be related. The purpose of random sampling is to assure that the sample is representative of the population. selection bias –in which some parts of the population are underrepresented in the sample Measurement bias—in which an instrument we use is faulty and introduces systematic error into our data

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## This note was uploaded on 04/29/2008 for the course MATH probstats taught by Professor Lukin during the Spring '08 term at Tulane.

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Probstats - A population is a collection of units of interest to us a variable would be a characteristic which could have different values for

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