confidence interval for a rate

This function create upper and lower CI for observed rate. Two new variables will be added LC and UC the formula is based on 95% CI: rate+/- 1.96 x sqrt((!!var x (1-!!var))/!!n_cases)

add_CI_values(data, var, n_cases)

Arguments

var

variable you want to sort

n_cases

number of cases used to calculate CI

Examples

library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union
tb = tibble::tibble(cs_rate = c(0.1, 0.3),
                    n_pt_cases = c(140, 234))
tb %>% 
 add_CI_values(var = cs_rate,
               n_cases = n_pt_cases)
#> # A tibble: 2 × 4
#>   cs_rate n_pt_cases     LC    UC
#>     <dbl>      <dbl>  <dbl> <dbl>
#> 1     0.1        140 0.0503 0.150
#> 2     0.3        234 0.241  0.359