variance_adjust {ruv}R Documentation

Adjust Estimated Variances

Description

Calculate rescaled variances, empirical variances, etc. For use with RUV model fits.

Usage

variance_adjust(fit, ebayes = TRUE, evar = TRUE, rsvar = TRUE, 
                bin = 10, rescaleconst = NULL)

Arguments

fit

A RUV model fit (a list), as returned by RUV2 / RUV4 / RUVinv / RUVrinv

ebayes

A logical variable. Should empirical bayes estimates be calculated?

evar

A logical variable. Should empirical variance estimates be calculated?

rsvar

A logical variable. Should rescaled variance estimates be calculated?

bin

The bin size to use when calculating empirical variances.

rescaleconst

Can be used to speed up execution. See get_empirical_variances.

Value

An RUV model fit (a list). In addition to the elements of the list returned by RUV2 / RUV4 / RUVinv / RUVrinv, the list will now contain:

sigma2.ebayes

Estimates of sigma^2 using the empirical bayes shrinkage method of Smyth (2004)

df.ebayes

Estimate of degrees of freedom using the empirical bayes shrinkage method of Smyth (2004)

varbetahat

"Standard" estimate of the variance of betahat

varbetahat.rsvar

"Rescaled Variances" estimate of the variance of betahat

varbetahat.evar

"Empirical Variances" estimate of the variance of betahat

varbetahat.ebayes

"Empirical Bayes" estimate of the variance of betahat

varbetahat.rsvar.ebayes

"Rescaled Empirical Bayes" estimate of the variance of betahat

p.rsvar

P-values, after applying the method of rescaled variances

p.evar

P-values, after applying the method of empirical variances

p.ebayes

P-values, after applying the empirical bayes method of Smyth (2004)

p.rsvar.ebayes

P-values, after applying the empirical bayes method of Smyth (2004) and the method of rescaled variances

p.BH

FDR-adjusted p-values

p.rsvar.BH

FDR-adjusted p-values, after applying the method of rescaled variances

p.evar.BH

FDR-adjusted p-values, after applying the method of empirical variances

p.ebayes.BH

FDR-adjusted p-values, after applying the empirical bayes method of Smyth (2004)

p.rsvar.ebayes.BH

FDR-adjusted p-values, after applying the empirical bayes method of Smyth (2004) and the method of rescaled variances

Author(s)

Johann Gagnon-Bartsch

References

Using control genes to correct for unwanted variation in microarray data. Gagnon-Bartsch and Speed, 2012. Available at: http://biostatistics.oxfordjournals.org/content/13/3/539.full.

Removing Unwanted Variation from High Dimensional Data with Negative Controls. Gagnon-Bartsch, Jacob, and Speed, 2013. Available at: http://statistics.berkeley.edu/tech-reports/820.

Linear models and empirical bayes methods for assessing differential expression in microarray experiments. Smyth, 2004.

See Also

RUV2, RUV4, RUVinv, RUVrinv, get_empirical_variances, sigmashrink

Examples

## Create some simulated data
m = 50
n = 10000
nc = 1000
p = 1
k = 20
ctl = rep(FALSE, n)
ctl[1:nc] = TRUE
X = matrix(c(rep(0,floor(m/2)), rep(1,ceiling(m/2))), m, p)
beta = matrix(rnorm(p*n), p, n)
beta[,ctl] = 0
W = matrix(rnorm(m*k),m,k)
alpha = matrix(rnorm(k*n),k,n)
epsilon = matrix(rnorm(m*n),m,n)
Y = X%*%beta + W%*%alpha + epsilon

## Run RUV-inv
fit = RUVinv(Y, X, ctl)

## Get adjusted variances and p-values
fit = variance_adjust(fit)

[Package ruv version 0.9.6 Index]