samplesize.bin {Hmisc} | R Documentation |

## Sample Size for 2-sample Binomial

### Description

Computes sample size(s) for 2-sample binomial problem given vector or scalar probabilities in the two groups.

### Usage

```
samplesize.bin(alpha, beta, pit, pic, rho=0.5)
```

### Arguments

`alpha` |
scalar ONE-SIDED test size, or two-sided size/2 |

`beta` |
scalar or vector of powers |

`pit` |
hypothesized treatment probability of success |

`pic` |
hypothesized control probability of success |

`rho` |
proportion of the sample devoted to treated group ( |

### Value

TOTAL sample size(s)

### AUTHOR

Rick Chappell

Dept. of Statistics and Human Oncology

University of Wisconsin at Madison

chappell@stat.wisc.edu

### Examples

```
alpha <- .05
beta <- c(.70,.80,.90,.95)
# N1 is a matrix of total sample sizes whose
# rows vary by hypothesized treatment success probability and
# columns vary by power
# See Meinert's book for formulae.
N1 <- samplesize.bin(alpha, beta, pit=.55, pic=.5)
N1 <- rbind(N1, samplesize.bin(alpha, beta, pit=.60, pic=.5))
N1 <- rbind(N1, samplesize.bin(alpha, beta, pit=.65, pic=.5))
N1 <- rbind(N1, samplesize.bin(alpha, beta, pit=.70, pic=.5))
attr(N1,"dimnames") <- NULL
#Accounting for 5% noncompliance in the treated group
inflation <- (1/.95)**2
print(round(N1*inflation+.5,0))
```

[Package

*Hmisc*version 5.1-3 Index]