Power {epiDisplay} R Documentation

## Power calculation for two sample means and proportions

### Description

Calculation of power given the results from a study

### Usage

```power.for.2p(p1, p2, n1, n2, alpha = 0.05)
power.for.2means(mu1, mu2, n1, n2, sd1, sd2, alpha = 0.05)
```

### Arguments

 `p1, p2` probabilities of the two samples `n1, n2` sample sizes of the two samples `alpha` significance level `mu1, mu2` means of the two samples `sd1, sd2` standard deviations of the two samples

### Details

These two functions compute the power of a study from the given arguments

### Author(s)

Virasakdi Chongsuvivatwong <cvirasak@medicine.psu.ac.th>

'n.for.2means', 'n.for.2p'

### Examples

```# Suppose, in the example found in 'help(n.for.2p)',
# given the two proportions are .8 and .6 and the sample size
# for each group is 60.

power.for.2p(p1=.8, p2=.6, n1=60, n2=60) # 59 percent

# If the means of a continuous outcome variable in the same
# two groups were 50 and 60 units and the standard deviations were 30
# and 35 units, then the power to detect a statistical significance
# would be

power.for.2means(mu1=50, mu2=60, sd1=30, sd2=35, n1=60, n2=60)
# 39 percent. Note the graphic display
```

[Package epiDisplay version 3.5.0.1 Index]