xcusum.crit: Compute decision intervals of CUSUM control charts

In spc: Statistical Process Control -- Calculation of ARL and Other Control Chart Performance Measures

Compute decision intervals of CUSUM control charts

Description

Computation of the decision intervals (alarm limits) for different types of CUSUM control charts monitoring normal mean.

Usage

xcusum.crit(k, L0, mu0 = 0, hs = 0, sided = "one", r = 30)

Arguments

k	reference value of the CUSUM control chart.
L0	in-control ARL.
mu0	in-control mean.
hs	so-called headstart (enables fast initial response).
sided	distinguishes between one-, two-sided and Crosier's modified two-sided CUSUM scheme by choosing "one", "two", and "Crosier", respectively.
r	number of quadrature nodes, dimension of the resulting linear equation system is equal to r+1 (one-, two-sided) or 2r+1 (Crosier).

Details

xcusum.crit determines the decision interval (alarm limit) for given in-control ARL L0 by applying secant rule and using xcusum.arl().

Value

Returns a single value which resembles the decision interval h.

Author(s)

Sven Knoth

See Also

xcusum.arl for zero-state ARL computation.

Examples

k <- .5
incontrolARL <- c(500,5000,50000)
sapply(incontrolARL,k=k,xcusum.crit,r=10) # accuracy with 10 nodes
sapply(incontrolARL,k=k,xcusum.crit,r=20) # accuracy with 20 nodes
sapply(incontrolARL,k=k,xcusum.crit)      # accuracy with 30 nodes

spc documentation built on Oct. 24, 2022, 5:07 p.m.