predIntPois() from EnvStats error with some set of numbers

[user4432]

Hi all,

I want to get the prediction intervals of the poisson probability distribution.
When I use the function predIntPois with this set of numbers predIntPois(c(70,73,80,66,62,64,73))
I get the error:
Error in ebinom(0, sum.x, ci = TRUE, ci.type = "two-sided", conf.level = 1 - :
'size' must be a postive integer at least as large as 'x'.

However if I change for example the last number of the set of numbers with 1 more or 1 less, I don't get an error. And it works perfectly. How is this possible?

predIntPois(c(70,73,80,66,62,64, 72))

Results of Distribution Parameter Estimation

Assumed Distribution: Poisson

Estimated Parameter(s): lambda = 69.57143

Estimation Method: mle/mme/mvue

Data: c(70, 73, 80, 66, 62, 64, 72)

Sample Size: 7

Prediction Interval Method: conditional

Prediction Interval Type: two-sided

Confidence Level: 95%

Number of Future Observations: 1

Prediction Interval: LPL = 48
UPL = 88*

Hopefully someone can help me. Thanks!

Anne

[DavoWW]

Hi @user4432,
Any duplicate values in x are causing the error:

predIntPois(c(70,73,80,66,62,64,73))$interval$limits  # Error

But this works:

predIntPois(c(70,73,80,66,62,64,73), k=1,
            method="conditional.approx.normal")$interval$limits  # No error

This may be a bug in the function. I have just contacted the package authors on GitHub to check.
HTH