ratioVariance {ssExtra}R Documentation

Volume to Basal Area Ratio Variance

Description

This routine will calculate the volume to basal area ratio variance estimate from an individual Monte Carlo simulation replicate and compare it with the value from the monte run. For more details see the User's Guide.

Usage

ratioVariance(ssBB,
              ssBB.mc,
              n = 25,
              mcSample = 1,
              stype = "bigBAF",
              runQuiet = FALSE,
              ...)

Arguments

ssBB

An object of class “ssBigBAF”.

ssBB.mc

An object of class “monteBigBAF”.

n

The sample size, n, desired from the simulations.

mcSample

The Monte Carlo sample replicate number for the specified sample size, n.

stype

‘bigBAF’ for tree stats on the big BAF surfaces; ‘count’ for the count surfaces.

runQuiet

TRUE: run without any feedback; FALSE: some feedback desired.

...

Gobbled.

Details

This routine will calculate the ratio variance for the volume-basal area ratio in (8.34) of Gregoire and Valentine (2008). The variance is calculated via their equations (8.42) & (8.43); both being found on p. 258–259. The estimate is calculated for a single Monte Carlo sample at a given sample size.

Value

msBB.mc

The results of a call to monteStatsBB for n and mcSample.

mtsBB.mc

The results of a call to monteTreeStatsBB for n and mcSample.

n

The requested sample size.

mcSample

The requested Monte Carlo sample replicate number.

df

A data frame with the variance of the mean and standard errors for the ratio and normal theory estimators.

means

A vector of means.

Note

Note that all of what is in this routine is also in the "monteBigBAF" constructor, but not through the use of this routine, which is simply made available as an easy way to calculate the variances for individual MC draws if desired, outside the framework of the constructor. The code in this routine is probably easier to understand than looking at the code in the constructor—specifically the requisite variances are calculated in monteStatsBB. It also demonstrates how one can extract the ratio variance estimate as well as a number of other quantities from the simulation results. This was originally the prototype code for the ratio variance calculations before it was added to the simulations through monteStatsBB.

Author(s)

Jeffrey H. Gove

References

See the vignette for this package—“A User's Guide to the ssExtra Package”—for an example and more information on the variance estimator and its use in the Monte Carlo simulations.

See Also

monteStatsBB

Examples

# Please see the user's guide for an example as it requires the output
# from a monte simulation run and is too lengthy to include here.

[Package ssExtra version 0.1-2 Index]