Unformatted text preview: than the pair C15 and C60.2
The drugs C15 and C60 are the same drug, but vary
in their potency. Usually, such data are analysed by
creating dichotomies among the levels of the response
variable. Possible dichotomies include comparing ‘very
good’ to ‘poor’, ‘good’ to ‘poor’, and so on. Standard
regression procedures, such as the logistic regression,
can then be utilized for data analyses.
Although such approaches are not incorrect, they
often result in a loss of information due to collapsing
(or ignoring) some categories of the response (unless In the study of the dependence of a response variable on
a set of independent variables, the choice of a model is
largely determined by the scale of measurement of the
response.1 Epidemiologists are often interested in estimating the risk of adverse events originally measured
on an interval scale (such as birthweight), but they often
choose to divide the outcome into two or more categories in order to compute an estimate of effect (risk
or odds ratio). Similarly, response vari...
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 Spring '11
 Regression Analysis, Logit, proportional odds, Ordinal Model

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