On 2019-03-14 19:43, Stefan Schreiber wrote:
Dear R users, While experimenting with the dbinom() function and reading its documentation (?dbinom) it reads that "dbinom gives the density" but shouldn't it be called "mass" instead of "density"? I assume that it has something to do with keeping the function for "density" consistent across discrete and continuous probability functions - but I am not sure and was hoping someone could clarify?
The Wikipedia article on "Probability density function" gives the "Formal definition" that, "the density of [a random variable] with respect to a reference measure ... is the Radon–Nikodym derivative".
This sounds bazaar to people who haven't studied measure-theoretic probability, but it allows a unified treatment of continuous and discrete probabilities and to others that are combinations and neither. The "reference measure" for a discrete probability distribution is the "counting measure", which supports the use of the word "density" in this context being equivalent to "mass". For continuous distributions, the "reference measure" is routinely taken to be the "improper prior" that assigns measure 1 to any unit interval on the real line.
Does that make it clear as mud? Spencer Graves https://en.wikipedia.org/wiki/Probability_density_function
Furthermore the help file for dbinom() function references a link (http://www.herine.net/stat/software/dbinom.html) but it doesn't seem to land where it should. Maybe this could be updated? Thank you, Stefan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
