LRneg {samplesizeestimator}

Sample Size for Estimating LR negative of a Single Diagnostic Test

Description

Calculate sample size(cases) based on negative likelihood ratio an unified index for comparing the accuracy of two diagnostic tests

Usage

LRneg(se, sp, lrneg, alp, pwr, k = 1)

Arguments

se

anticipated sensitivity of the diagnostic test

sp

anticipated specificity of the diagnostic test

lrneg

anticipated LR negative value

alp

level of significance

pwr

desired level of power

k

number of control(s) per case

Value

a list object with minimum required sample size with reporting

Author(s)

R. Amala, Scientist-C, ICMR-VCRC, Puducherry & G. Kumarapandiyan, Asst. Prof., Madras Christian College, Chennai

References

Simel, D.L., Samsa, G.P. Matchar, D. B. (1991). Likelihood ratio with confidence: sample size estimation for diagnostic test studies. J Clin Epidemiol. 44: 763-70.

Examples

LRneg(se=0.9, sp=0.5,lrneg=0.4,alp=0.05, pwr=0.8,k=1)