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jackstraw (version 1.1)

jackstraw.parametric: Parametric Jackstraw

Description

Estimates statistical significance of association between variables and their latent variables, from a parametric jackstraw procedure.

Usage

jackstraw.parametric(dat, FUN = function(x) fast.svd(x)$v[, 1:r, drop =
  FALSE], noise = function(x) rnorm(x, mean = 0, sd = 1), r = NULL,
  r1 = NULL, s = NULL, B = NULL, covariate = NULL, verbose = TRUE,
  seed = NULL)

Arguments

dat

a data matrix with m rows as variables and n columns as observations.

FUN

provide a function to estimate LVs. Must output r estimated LVs in a n*r matrix.

noise

specify a parametric distribution to generate a noise term.

r

a number of significant latent variables.

r1

a numeric vector of latent variables of interest.

s

a number of ``synthetic'' null variables. Out of m variables, s variables are independently permuted.

B

a number of resampling iterations.

covariate

a model matrix of covariates with n observations. Must include an intercept in the first column.

verbose

a logical indicator as to whether to print the progress.

seed

a seed for the random number generator.

Value

jackstraw.parametric returns a list consisting of

p.value

the m p-values of association tests between variables and their principal components

obs.stat

the observed F-test statistics

null.stat

the s*B null F-test statistics

Details

This function estimates statistical significance of association between variables and latent variables using a parametric distribution of a noise term. A small number s of observed variables are replaced by synthetic null variables generated from a specified distribution (such as Normal(0,1)). After applying a latent variable estimation function on this newly generated matrix (with s synthetic nulls and m-s intact observed variables), F-test statistics between estimated latent variables and s synthetic nulls are called the jackstraw statistics. P-values are computed by comparing observed F-test statistics against s*B jackstraw statistics.

Note that unless you have a strong reason to use a parametric distribution, it is advised to use the non-parametric jackstraw.

See Also

jackstraw.FUN

jackstraw