NNTintervalsRetrospective: NNTintervalsRetrospective

In professorbeautiful/NNTbiomarkerHome: Calculate Design Parameters for Biomarker Validation Studies

Description

Bayes predictive intervals for sensitivity, specificity, NNTpos and NNTneg in a case-control retrospective study.

Usage

NNTintervalsRetrospective(Ncases = 10, Ncontrols = 30, NposCases = 6,
  NposControls = 2, prev = 0.15, alpha = 0.025, prior = c(1/2, 1/2))

Arguments

Ncases	Number of cases in the study
Ncontrols	Number of controls in the study
NposCases	Number of cases with positive test
NposControls	Number of controls with positive test
prev	Prevalence of the BestToTreat (versus BestToWait)
alpha	Significance level for interval.
prior	Beta parameters for prior. Default is the Jeffreys prior = c(1/2,1/2). Jaynes prior = c(0,0) won't work when #fp=1.

Value

A list with 3 components containing intervals (predictive or otherwise), with names intervalsForSN, intervalsForSP, intervalsForNNT. The intervals derive from assuming independent Jeffreys priors for SN and SP, sampling from joint independent posteriors for SN and SP incorporating the anticipated results, and applying NNT.from.sesp (Bayes theorem) to each sampled pair to obtain a sample of NNTpos and NNTneg.

professorbeautiful/NNTbiomarkerHome documentation built on June 7, 2019, 8:28 a.m.