Description Usage Arguments Details Value Methods (by class) References Examples
Test on device-events using the x-bar control chart. Includes the first 4 Western Electric rules common to statistical process control.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |
df |
Required input data frame of class
|
... |
Further arguments passed onto |
ts_event |
Required if Default: Example: |
analysis_of |
Optional string indicating the English description of what
was analyzed. If specified, this will override the name of the
Default: Example: |
eval_period |
Optional positive integer indicating the number of unique times counting in reverse chronological order to assess. This will be used to establish the process mean and moving range. Default: |
zero_rate |
Required maximum proportion of Default: |
we_rule |
Required integer from Default: |
mu |
Optional value of the in-control process mean, typically measured from historical data. Default: |
sigma |
Optional value of the in-control process standard deviation, typically measured from historical data. Default: |
Function xbar()
is an implementation of the x-bar
Control Chart test from the family of statistical process control tests
originally proposed by Walter Shewhart.
we_rule
has four possible values: 1
is one point over the
3-sigma limit. 2
is two out of three consecutive points over the
2-sigma limit. 3
is four of five consecutive points over the 1-sigma
limit. 4
is nine consecutive points over the process mean.
A named list of class mdsstat_test
object, as follows:
Name of the test run
English description of what was analyzed
Named boolean of whether the test was run. The name contains the run status.
A standardized list of test run results: statistic
for the test statistic, lcl
and ucl
for the 95
confidence bounds, p
for the p-value, signal
status, and
signal_threshold
.
The test parameters
The data on which the test was run
mds_ts
: x-bar on mds_ts data
default
: x-bar on general data
Montgomery, Douglas C. Introduction to Statistical Quality Control by Douglas C. Montgomery, 5th Edition: Study Guide. Cram101, 2013.
1 2 3 4 5 6 7 8 9 | # Basic Example
data <- data.frame(time=c(1:25), event=as.integer(stats::rnorm(25, 100, 25)))
a1 <- xbar(data)
# Example using an mds_ts object
a2 <- xbar(mds_ts[[3]])
# Example using a derived rate as the "event"
data <- mds_ts[[3]]
data$rate <- ifelse(is.na(data$nA), 0, data$nA) / data$exposure
a3 <- xbar(data, c(Rate="rate"))
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