Apparent prevalence from known prevalence

The observed counts of disease is going to be a binomial but with the apparent prevalence as a probability. This will never be less than (1-specificity) of the test (and never more than the sensitivity). When either of those quantities are uncertain the shape of the distribution of observed counts is not clear cut.

Usage

apparent_prevalence(p, sens, spec)

Arguments

p

the true value of the prevalence

sens

the sensitivity of the test

spec

the specificity of the test

Value

the expected value of apparent prevalence

Examples

apparent_prevalence(0, 0.75, 0.97)
#> [1] 0.03
apparent_prevalence(1, 0.75, 0.97)
#> [1] 0.75