Construction of Operating Characteristic (OC) curve

oc_plan provides the Operating Characteristic (OC) curve for known microbiological distribution such as lognormal. The probability of acceptance is plotted against mean log10 concentration.

oc_plan(c, r, t, distribution, K, m, sd)

Arguments

c

acceptance number

r

number of primary increments in a grab sample or grab sample size

t

number of grab samples

distribution

what suitable distribution we have used such as 'Poisson gamma' or 'Lognormal' or 'Poisson lognormal'

K

dispersion parameter of the Poisson gamma distribution (default value 0.25)

m

microbiological limit with default value zero, generally expressed as number of microorganisms in specific sample weight

sd

standard deviation of the lognormal and Poisson-lognormal distributions on the log10 scale (default value 0.8)

Value

Operating Characteristic (OC) curve

Details

Based on the food safety literature, mean concentration is given by \(\lambda = 10^{\mu+log(10)\sigma^2/2}\).

See also

prob_accept

Examples

  c <-  0
  r <-  25
  t <-  30
  distribution <- 'Poisson lognormal'
  oc_plan(c, r, t, distribution)