mqcs.mewma {qcr}

Function to plot mewma chart

Description

This function is used to compute statistics required by the mewma chart.

Usage

mqcs.mewma(x, ...)

## Default S3 method:
mqcs.mewma(
  x,
  data.name = NULL,
  limits = NULL,
  Xmv = NULL,
  S = NULL,
  method = "sw",
  plot = FALSE,
  ...
)

## S3 method for class 'mqcd'
mqcs.mewma(
  x,
  limits = NULL,
  Xmv = NULL,
  S = NULL,
  lambda = 0.1,
  method = "sw",
  plot = FALSE,
  ...
)

Arguments

x

an R object (used to select the method). See details.

...

arguments passed to or from methods.

data.name

a string that specifies the title displayed on the plots. If not provided it is taken from the name of the object's data.

limits

a two-values vector specifying the control limits.

Xmv

is the mean vector. It is only specified for Phase II or when the parameters of the distribution are known.

S

is the sample covariance matrix. It is only used for Phase II or when the parameters of the distribution are known.

method

is the method employed to compute the covatiance matrix in the individual observation case. Two methods are used "sw" for compute according to (Sullivan,Woodall 1996a) and "hm" by (Holmes,Mergen 1993)

plot

a logical value indicating that it should be plotted.

lambda

is the smoothing constant. Only values of 0.1, 0.2,...,0.9 are allowed.

Author(s)

Edgar Santos-Fernandez

Examples

##
##  Continuous data 
##
library(qcr)
data(dowel1)
str(dowel1)
data.mqcd <- mqcd(dowel1)
res.mqcs <- mqcs.mewma(data.mqcd)
summary(res.mqcs)
plot(res.mqcs, title =" MEWMA Control Chart for dowel1")