R: Agresti-Coull add-4 CI for a binomial proportion

add4ci {PropCIs} | R Documentation

## Agresti-Coull add-4 CI for a binomial proportion

### Description

Agresti-Coull add-4 CI for a binomial proportion, based on adding 2 successes and 2 failures before computing the Wald CI. The CI is truncated, when it overshoots the boundary

### Usage

    add4ci(x, n, conf.level)

### Arguments

`x` | number of successes
`n` | number of trials
`conf.level` | confidence coefficient

### Value

A list with class '"htest"' containing the following components:

`conf.int` | The confidence intervall for the proportion
`estimate` | The estimator for the proportion

### References

Agresti, A., Coull, B. (1998) Approximate is better than exact for interval estimation of binomial proportions. The American Statistician 52, 119–126.

Agresti, A., Caffo, B.(2000) Simple and effective confidence intervals for proportions and difference of proportions result from adding two successes and two failures. The American Statistician 54 (4), 280–288.

### Examples

    add4ci(x = 15, n = 112, conf.level = 0.95)

[Package PropCIs version 0.3-0 Index]