Ims {LTPDvar}

Inspection cost function

Description

mean inspection cost per lot of process average quality, assuming that the sample is inspected by variables and the remainder of rejected lots is inspected by attributes, divided by parameter cm (cost of inspecting one item by variables divided by cost of inspecting the item by attributes)

Usage

Ims(n, k, N,  pbar, cm = 1,type = c("exact", "napprox","ewmaSK","ewma2"),lam=1)

Arguments

n

sample size

k

critical value of the samping plan

N

lot size (number of items in the lot)

pbar

process average fraction defective

cm

cost of inspection of one item by variables divided by cost of inspection of the item by attributes, default value 1

type

type of OC (operating characteristic) used, either "exact" (default) using non-central t-distribution, or "napprox" for approximate OC; if EWMA statistic is to be used, "ewmaSK" stands for the sigma known case, "ewma2" stands for the sigma unknown case

lam

smoothing parameter in case that EWMA statistic is used

Value

single value

See Also

LTPDvar-package

Examples

Ims(20, 2.58555,1000, 0.001 ,1.5,type="ewmaSK",lam=1 )