Estimate for the extended Youden index, the associated optimal cut-points using normal and non-parametric methods and the associated. The sample size to estimate the extended Youden index of a diagnostic marker within a given margin of error under normal assumptions is also provided.
Calculate the variance estimation for the extended Youden index and the variance estimation for the associated lower and upper optimal cut-point assuming that a diagnostic test follows normal distributions in the three ordinal groups (D^-,D^0,D^+).
Statistical test to compare the summary measure (VUS or Youden) estimates between two markers or multiple markers assuming that the marker follows normal distribution in each diagnosis group, for both independent samples and paired samples.
The wrapper function provide not only point estimates but also variances for the extended Youden index for three ordinal groups, the associated optimal cut-points under parametric and non-parametric methods and sample size under normal.
For a diagnostic test folling normal distributions, given the true or estimated normal distribution mean and standard deviation (SD) parameters for three ordinal diagnostic groups, ,calculate the Youden index and optimal cut point estimations for three ordinal diagnostic groups (usllay healthy D- , mildly diseased D0 and diseased D+).
A wrapper function to calculate the Volume under Surface (VUS) estimate, its variance estimate and optimal cut-point, under normal and nonparametric assumption, to provide partial VUS estimate with a minimum requirement on the specificity and sensitivity under normality and to calculate the sample size under normality to achieve a certain estimation precision on VUS estimate.
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