Nonparametric tolerance interval with MASS package

Question

In R, using the 'geyser' dataset from the MASS library, we are building a nonparametric tolerance interval cont. 90% of geyser eruptions w/ 99% CI

Please, find below the equation I am using:

no_param_pi <- function(x, conf.level = 0.90) {
  n <- length(x)
  x <- sort(x)
  j <- max(floor((n + 1) * (1 - conf.level) / 2), 1)
  conf.level <- (n + 1 - 2 * j)/(n + 1)
  interval <- c(x[j], x[n + 1 - j])
  attr(interval, "conf.level") <- conf.level
  interval
}

Here is the code I am playing with, and in which I am missing something... :

library(MASS)
library(tolerance)
head(geyser)

eruptions = subset(geyser, select = waiting:duration, increasing)

nptol.int(eruptions, alpha = 1 - 0.99, P = 0.9)

Looking for both

Hi. Can you provide a sample of your data? You can use function `dput(head(eruptions))` and copy the output as a code in your Question. — Bloxx, Feb 09 '22 at 23:25
structure(list(), .Names = character(0), row.names = c(NA, 6L ), class = "data.frame") — Brittney Bates, Feb 09 '22 at 23:49
Can you provide an error that you receive after running your code? — Bloxx, Feb 09 '22 at 23:51
Error in nptol.int(eruptions, alpha = 1 - 0.99, P = 0.9) : It is not meaningful to compute tolerance intervals using vectors of length less than 2! — Brittney Bates, Feb 09 '22 at 23:57
I feel that my eruptions is coded incorrectly, but I'm not sure how....Would the original question be helpful? — Brittney Bates, Feb 09 '22 at 23:58
Are you interested in tolerance intervals for variable `waiting` or `duration` or both? — Bloxx, Feb 10 '22 at 00:04

score 0 · Answer 1 · answered Feb 10 '22 at 00:12

Can you try these few lines of code:

eruptions <- geyser
nptol.int(eruptions$duration, alpha = 1 - 0.99, P = 0.9, side = 1)
nptol.int(eruptions$duration, alpha = 1 - 0.99, P = 0.9, side = 2)
nptol.int(eruptions$waiting, alpha = 1 - 0.99, P = 0.9, side = 1)
nptol.int(eruptions$waiting, alpha = 1 - 0.99, P = 0.9, side = 2)

Is this what are you looking for? You have many variations, so I suggest you look documentation under Help. ?nptol.int

Thank you for all of your help! – Brittney Bates Feb 10 '22 at 00:14 — Brittney Bates, Feb 10 '22 at 00:14

Nonparametric tolerance interval with MASS package

1 Answers1