Talk:Continuous or discrete variable: Difference between revisions

Revision as of 16:52, 30 April 2015

Revision as of 16:53, 30 April 2015

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::--[[User:GodMadeTheIntegers|GodMadeTheIntegers]] ([[User talk:GodMadeTheIntegers|talk]]) 16:32, 30 April 2015 (UTC)

:::That's a dictionary intended primarily for statistics, apparently concerning continuous and discrete random variables. We already have an article discussing that concept (namely [[random variable]]). Also, if we want to start the article "in mathematics", then the appropriate distinction is certainly not whether the variable can assume uncountable many values. There are uncountable sets that are not continua and countable sets that are not discrete. Better sources than this are presumably required. [[User:Sławomir Biały|<span style="text-shadow:grey 0.3em 0.3em 0.1em; class=texhtml">Sławomir Biały</span>]] ([[User talk:Slawekb|talk]]) 16:46, 30 April 2015 (UTC)

:::: This proposal from GodMadeTheIntegers won't work at all. What if the set of possible values is the set of all irrational numbers.? That has plenty of gaps, so it's not continuous by the gaplessness characterization, and I don't see how one could call it discrete. Moreover, many lay readers will think "uncountable" means simply "infinite" and conclude that this article says that if the set of all possible values is the set of all integers, then the variable is continuous. A probability or statistics textbook may explain discrete and continuous probability distributions, and we already have material on that. I would characterize discrete probability distributions not by countability but be the fact that the distribution consists only of point masses, so that

:::::: <math> 1 = \sum_x f(x) </math>

:::: where ''&fnof;'' is the probability mass function. Statistics textbooks may also have other relevant material on measurement rather than on probability distributions, but that still covers only a fragment of the topic. [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 16:52, 30 April 2015 (UTC)