R: Calculate Descriptive Summary Statistics on Ring-Width Series

rwl.stats {dplR} | R Documentation

## Calculate Descriptive Summary Statistics on Ring-Width Series

### Description

This function calculates descriptive statistics on a `rwl` object of raw or detrended ring-width series.

### Usage

    rwl.stats(rwl)

    ## S3 method for class 'rwl'
    summary(object, ...)

### Arguments

`rwl, object` | a `rwl` object with (usually) raw ring-width series as columns and years as rows such as that produced by `read.rwl`. It is sometimes desirable to run this on detrended (e.g., rwi) data.
`...` | Additional arguments from the generic function. These are silently ignored.

### Details

This calculates a variety of descriptive statistics commonly used in dendrochronology (see below). Users unfamiliar with these should see Cook and Kairiukstis (1990) and Fritts (2001) for further details.

The `summary` method for class `"rwl"` is a wrapper for `rwl.stats`.

### Value

A `data.frame` containing descriptive stats on each `"series"`. These are the first and last year of the series as well as the length of the series (`"first"`, `"last"`, `"year"`). The mean, median, standard deviation are given (`"mean"`, `"median"`, `"stdev"`) as are the skewness, the Gini coefficient, and first order autocorrelation (`"skew"`, `"gini.coef"`, `"ar1"`).

Note that prior to version 1.6.8, two measures of sensitivity were also included. However mean sensitivity is not a robust statistic that should rarely, if ever, be used (Bunn et al. 2013). Those sensitivity functions (`"sens1"` and `"sens2"`) are still available for continuity. Users should consider the coef of variation in lieu of mean sensitivity.

### Author(s)

Andy Bunn. Slightly improved by Mikko Korpela.

### References

Bunn, A. G., Jansma, E., Korpela, M., Westfall, R. D., and Baldwin, J. (2013) Using simulations and data to evaluate mean sensitivity (zeta) as a useful statistic in dendrochronology. Dendrochronologia, 31(3), 250–254.

Cook, E. R. and Kairiukstis, L. A., editors (1990) Methods of Dendrochronology: Applications in the Environmental Sciences. Springer. ISBN-13: 978-0-7923-0586-6.

Fritts, H. C. (2001) Tree Rings and Climate. Blackburn. ISBN-13: 978-1-930665-39-2.

### See Also

`rwi.stats`, `read.rwl`

### Examples

    library(utils)
    data(ca533)
    rwl.stats(ca533)
    summary(ca533)

[Package dplR version 1.7.1 Index]