Create an object of class 'qcs' to perform statistical quality control.
This object may then be used to plot Shewhart charts, Multivariate Control Charts,
and more.
a scalar with the column number corresponding the index each
group (sample).
sizes
a value or a vector of values specifying the sample sizes
associated with each group. For continuous data the sample sizes are obtained counting the non-NA elements of
the sample.index vector. For "p", "np" and "u" charts the argument
sizes is required.
type
a character string specifying the group statistics to compute:
Statistic charted
Chart description
"xbar"
mean
means of a continuous process variable
"R"
range
ranges of a continuous process variable
"S"
standard deviation
standard deviations of a continuous
variable
"one"
mean
one-at-time data of a
continuous process variable
"p"
proportion
proportion
of nonconforming units
"np"
count
number of
nonconforming units
"c"
count
nonconformities per unit
"u"
count
average nonconformities per unit
"g"
count
number of non-events between events
center
a value specifying the center of group statistics or the
”target” value of the process.
std.dev
a value or an available method specifying the within-group standard
deviation(s) of the process. Several methods are available for estimating the
standard deviation in case of a continuous process variable.
conf.nsigma
a numeric value used to compute control limits, specifying the
number of standard deviations (if conf.nsigma > 1) or the confidence level (if 0
< conf.nsigma < 1).
limits
a two-values vector specifying control limits.
type.data
a string specifying el type de data.
lambda
the smoothing parameter 0 <= lambda
<= 1
nsigma
a numeric value used to compute control limits, specifying the
number of standard deviations.
decision.interval
A numeric value specifying the number of standard
errors of the summary statistics at which the cumulative sum is out of
control.
se.shift
The amount of shift to detect in the process, measured in
standard errors of the summary statistics.
Value
Returns an object of class 'qcs'.
References
Montgomery, D.C. (2000) Introduction to Statistical
Quality Control, 4th ed. New York: John Wiley & Sons. Wetherill, G.B.
and Brown, D.W. (1991) Statistical Process Control. New York:
Chapman & Hall.