# Plot diagram of sample size vs. test power

### Description

Plot a diagram to illustrate the relationship of sample size and test power for a given set of parameters.

### Usage

1 2 |

### Arguments

`x` |
object of class power.htest usually created by one of the power calculation functions, e.g., pwr.t.test() |

`...` |
Arguments to be passed to |

### Details

Power calculations for the following tests are supported: t-test (pwr.t.test(), pwr.t2n.test()), chi squared test (pwr.chisq.test()), one-way ANOVA (pwr.anova.test(), standardnormal distribution (pwr.norm.test()), pearson correlation (pwr.r.test()), proportions (pwr.p.test(), pwr.2p.test(), pwr.2p2n.test()))

### Value

These functions are invoked for their side effect of drawing on the active graphics device.

### Note

By default it attempts to use the plotting tools of ggplot2 and scales. If they are not installed, it will use the basic R plotting tools.

### Author(s)

Stephan Weibelzahl <weibelzahl@pfh.de>

### See Also

`pwr.t.test`

`pwr.p.test`

`pwr.2p.test`

`pwr.2p2n.test`

`pwr.r.test`

`pwr.chisq.test`

`pwr.anova.test`

`pwr.t2n.test`

### Examples

1 2 3 4 | ```
## Two-sample t-test
p.t.two <- pwr.t.test(d=0.3, power = 0.8, type= "two.sample", alternative = "two.sided")
plot(p.t.two)
plot(p.t.two, xlab="sample size per group")
``` |