pear (version 1.2)

peboxplot: boxplots of a periodic time series

Description

Side-by-side boxplots are produced for each period in a periodic time series. These plots can reveal many important features in a periodic time series such as the need for a variance stablizing transformation, outliers, heteroscedasticity not removable by a power transformation, etc. The peboxplot is a useful adjunct to the Splus functions tsplot and monthplot.

Usage

peboxplot(z, ...)

Arguments

z

a univariate time series object. Note that the period of z is given by attr(z, "tsp")[3]. Additional information about the time series can be provided in a title string by setting attr(z, "title") to the desired string. This title will then be displayed on the plot. Abbreviations for the periods may be provided in attr(z, "abb"). For example, to use the standard monthly abbreviations: attr(z, "abb")<-month.abb. These abbreviations will be used to aid one in interpreting the output.

...

optional arguments which are passed to the boxplot function

Value

No output is produced. Plot is a 'side effect'.

Side Effects

plot produced

Details

Boxplots of seasonal data are vary useful in many applications. See Hipel and McLeod (1994) for examples.

References

Hipel, K.W. and McLeod, A.I. (1994) "Time Series Modelling of Water Resources and Environmental Systems" Elsevier, Amsterdam ISBN 0--444--89270--2. (1013 pages).

See Also

peplot, monthplot, tsplot

Examples

data(Fraser)
peboxplot(log(Fraser))