# R/nLogOdds.R In PracTools: Tools for Designing and Weighting Survey Samples

#### Documented in nLogOdds

```nLogOdds <- function(moe.sw, e, alpha=0.05, pU, N=Inf){
if (!(moe.sw==1 | moe.sw==2))
stop("moe.sw must equal 1 or 2.\n")
if (alpha <= 0 | alpha >= 1)
stop("alpha must be in (0,1).\n")
if (sum(sapply(list(e, N, pU), is.null) != 0))
stop("e, N, and pU cannot be NULL.\n")
pU.chk <- any(pU <= 0) | any(pU >= 1)
if (pU.chk) stop("pU must be in (0,1).\n")

if (N <= 0) stop("N must be positve.\n")

if (N == Inf) {a <- 1}
else {a <- N/(N-1)}

z <- qnorm(1 - alpha/2)
qU <- 1-pU
k <- qU/pU

if (moe.sw == 1){
rad <- e^2*(1 + k^2)^2 + k^2 * (1 - 2*e)*(1 + 2*e)
}
if (moe.sw == 2){
e <- e*pU
rad <- e^2*(1 + k^2)^2 + k^2 * (1 - 2*e)*(1 + 2*e)
}
x <- e*(1 + k^2) + sqrt(rad)
x <- x / (k * (1 - 2*e))

n.sam <- a * (sqrt(pU*qU)/z * log(x))^2 + 1/N
n.sam <- 1/n.sam
n.sam
}
```

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PracTools documentation built on Aug. 17, 2022, 5:06 p.m.