# power.t.test.FDR: Power calculations for one and two sample t tests using FDR... In ssize: Estimate Microarray Sample Size

## Description

Compute power of test, or determine parameters to obtain target power.

## Usage

 ```1 2 3 4 5 6``` ```power.t.test.FDR(sd=1, n=NULL, delta=NULL, FDR.level=0.05, pi0, power=NULL, type=c("two.sample", "one.sample", "paired"), alternative=c("two.sided", "one.sided") ) ```

## Arguments

 `sd` Standard deviation `n` Number of observations (per group) `delta` True difference in means `FDR.level` False Discovery Rate (expected ratio of false discoveries among all discoveries) `pi0` Proportion of true null hypothesies (fraction of tests that with no difference) `power` Power of test (1 minus Type II error probability) `type` Type of t test `alternative` One- or two-sided test

## Details

Exactly one of the parameters `n`, `delta`, `power`, `sd`, and `FDR.level` must be passed as NULL, and that parameter is determined from the others. Notice that the last two have non-NULL defaults so NULL must be explicitly passed if you want to compute them.

## Value

Object of class `"power.htest"`, a list of the arguments (including the computed one) augmented with `method` and `note` elements.

## Note

`uniroot` is used to solve power equation for unknowns, so you may see errors from it, notably about inability to bracket the root when invalid arguments are given.

## Author(s)

Peng Liu, based on `power.t.test` code by Peter Dalgaard, which in turn is based on previous work by Claus Ekstrøm

## See Also

`t.test`, `uniroot`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18``` ``` ## Compute power given sd, n, delta, FDR & pi.0 power.t.test.FDR(sd=1, n=5, delta=2, FDR.level=0.05, pi0=0.95, power=NULL, type="two.sample", alternative="two.sided") ## Compute power power.t.test.FDR(n=20, delta=1, FDR=0.05, pi0=0.75) power.t.test.FDR(n=29, delta=1, FDR=0.05, pi0=0.75) ## compute n power.t.test.FDR(n=NULL, sd=1, power=.90, delta=1, FDR=0.05, pi0=0.975) power.t.test.FDR(n=NULL, sd=1, power=.90, delta=1, FDR=0.05, pi0=0.975, alt="one.sided") ## compute sd power.t.test.FDR(sd=NULL, n=29, power=.90, delta=1, FDR=0.05, pi0=0.975) ## compute FDR level power.t.test.FDR(sd=1, n=29, power=.90, delta=1, FDR=NULL, pi0=0.975) ```

ssize documentation built on May 6, 2019, 3:34 a.m.