xBar_sBar_LCL {ggQC}

Mean of Subgroup Means Lower Control Limit (LCL) based on Standard Deviation

Description

Calculates the mean of subgroup means lower control limit based on the standard deviation. The result is used when constructing a xBar-S charts.

Usage

xBar_sBar_LCL(data, value, grouping, n = NULL, natural = F,
  formula = NULL)

Arguments

data

data frame to be processed

value

numeric vector in a data frame with values of interest.

grouping

single factor/variable to split the data frame "values" by.

n

a number indicating a hypothetical subgroup size other than, function determined subgroup n determined by the floor length of subgroup values.

natural

logical, if TRUE calculate limits for individuals (n=1) else calculate for n determined by the floor length of subgroup values

formula

a formula, such as y ~ x1 + x2, where the y variable is numeric data to be split into groups according to the grouping x factors/variables

Value

A number; mean of subgroup means Lower Control Limit (LCL) based on standard deviation

Examples

set.seed(5555)
df <- data.frame(v=rnorm(60, 0, 1), g=rep(c("A","B","C","D","E"), each=12))
xBar_sBar_LCL(data = df, formula = v~g)