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October 22, 2017 21:47
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| # Listing B.20 Exact binomial sample size calculation | |
| errorProb <- function(targetRate,difference,size) { | |
| pbinom( | |
| ceiling(( targetRate - difference) * size), | |
| size = size, prob = targetRate) | |
| } | |
| print(errorProb(0.045 , 0.004, est)) ## [1] 0.04153646 | |
| binSearchNonPositive <- function(fEventuallyNegative) { | |
| low <- 1 | |
| high <- low + 1 | |
| while(fEventuallyNegative(high) > 0) { | |
| high <- 2 * high | |
| } | |
| while(high > low + 1) { | |
| m <- low + (high-low) %/% 2 | |
| if(fEventuallyNegative(m) > 0) { | |
| low <- m | |
| } else { | |
| high <-m | |
| } | |
| } | |
| high | |
| } | |
| actualSize <- function(targetRate, difference, errorProb) { | |
| binSearchNonPositive(function(n) { | |
| errorProb(targetRate, difference, n) - errorProb | |
| }) | |
| } | |
| size <- actualSize(0.045, 0.004, 0.05) | |
| print(size) ## [1] 7623 print(errorProb(0.045,0.004,size)) ## [1] 0.04983659 |
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