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help for fagani
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Fagan's bayesian nomogram

    fagan #prev #lrp #lrn [, options]

    where
    #prev is the prior or pretest probability of disease
    #lrp is the likelihood ratio of a positive test result
    #lrn the likelihood ratio of a negative test result

Description

    fagani creates a plot showing the relationship between the prior
        probability, the LR (combination of sensitivity and specificity), and
        the posterior probability.
 

Remarks

    It is an immediate command, see help immed.
    When Bayes theorem is expressed in terms of log-odds, the posterior
        log-odds are a linear function of the prior log-odds and the log
        likelihood ratio.
    fagan plots an axis on the left with the prior log-odds, an axis in the
        middle representing the log likelihood ratio and an axis on the right
        representing the posterior log-odds.
  
    Lines are drawn from the prior probability on the left through the LRs in
        the center and extended to the respective posterior probability on
        the right.

Options

    legendopts(#) specify options that affect the plot legend.
    ysize() and xsize() specify the height and width of plot respectively.



Example

        . fagani 0.5 14.4 0.25 

        . fagani 0.25 20 0.05, ysize(8) xsize(6) 

        . fagani 0.45 6.4 0.25, scheme(s2mono) 


    
Author

    Ben Adarkwa Dwamena, Division of Nuclear Medicine, Department of
    Radiology, University of Michigan Medical School, Ann Arbor, Michigan.