pareto.chart {qcc}

Pareto chart

Description

Computes a table of statistics and plot a Pareto chart.

Usage

pareto.chart(data, plot = TRUE, ...)

## S3 method for class 'pareto.chart'
plot(x, xlab = NULL, ylab = "Frequency", 
     ylab2 = "Cumulative Percentage", 
     cumperc = seq(0, 100, by = 25), 
     ylim = NULL, main = NULL,
     col = blues.colors(nlevels), 
     ...) 

Arguments

data

a vector of values. names(data) are used for labelling the bars.

plot

a logical specifying if the chart should be provided (TRUE, default).

x

the object of class 'pareto.chart' returned by a call to pareto.chart function.

xlab

a string specifying the label for the x-axis.

ylab

a string specifying the label for the y-axis.

ylab2

a string specifying the label for the second y-axis on the right side.

cumperc

a vector of percentage values to be used as tickmarks for the second y-axis on the right side.

ylim

a numeric vector specifying the limits for the y-axis.

main

a string specifying the main title to appear on the plot.

col

a value for the color, a vector of colors, or a palette for the bars. See the help for colors and palette.

...

other graphical arguments to be passed to the corresponding plot method, and eventually to the barplot function.

Details

A Pareto chart is a barplot where the categories are ordered in non increasing order, and a line is also added to show the cumulative sum.

Value

Returns an object of class 'pareto.chart' containing the descriptive statistics used to draw the Pareto chart. This object has associated a print and plot mehod.

Author(s)

Luca Scrucca

References

Mason, R.L. and Young, J.C. (2002) Multivariate Statistical Process Control with Industrial Applications, SIAM.
Montgomery, D.C. (2005) Introduction to Statistical Quality Control, 5th ed. New York: John Wiley & Sons.
Ryan, T. P. (2000), Statistical Methods for Quality Improvement, 2nd ed. New York: John Wiley & Sons, Inc.
Scrucca, L. (2004). qcc: an R package for quality control charting and statistical process control. R News 4/1, 11-17.
Wetherill, G.B. and Brown, D.W. (1991) Statistical Process Control. New York: Chapman & Hall.

See Also

barplot

Examples

defect <- c(80, 27, 66, 94, 33)
names(defect) <- c("price code", "schedule date", "supplier code", "contact num.", "part num.")
pareto.chart(defect, ylab = "Error frequency")
pareto.chart(defect, ylab = "Error frequency", xlab = "Error causes", las=1)
pareto.chart(defect, ylab = "Error frequency", col=rainbow(length(defect)))
pareto.chart(defect, cumperc = seq(0, 100, by = 5), ylab2 = "A finer tickmarks grid")