Library: | spc |
See also: | spcewma1c spcewma1arl spcewma1ad spcewma1pmf spcewma2 |
Quantlet: | spcewma1 | |
Description: | graphical representation of a one-sided EWMA chart for given data, critical value and smoothing parameter lambda |
Usage: | spcewma1(lambda, c, zreflect, observed) | |
Input: | ||
lambda | scalar, containing the smoothing parameter | |
c | scalar, representing the critical value. It is computed in order to provide an in-control ARL. | |
zreflect | scalar, representing a pre-specified border. It is usually less than zero. | |
observed | n x 1 vector of user-defined data |
This quantlet includes an in-control ARL computation.
; One-sided EWMA chart for 100 pseudorandom variables ; with normal distribution, where the first 80 observations ; have mean = 0 and the next 20 have mean = 1. The chart ; parameters are lambda = 0.1, in-control ARL = 300 and ; zreflect = -4: library("spc") mean = #(matrix(80) .* 0, matrix(20) .* 1) randomize(31) observed = normal(100) + mean c = spcewma1c(300,.1,-4,50) spcewma1( .1, c, -4, observed)
A display showing the one-sided EWMA chart. An alarm is signaled at t = 93.