What is a P-Value in Simple English?



Simple explanation of P-value
A P-Value is a measure of how rare a particular outcome is given an assumption. For example, someone tells you they are a 90% Free Throw shooter in Basketball. You doubt their claim and request they step up to the free throw line and shoot 10 shots. They make 5 out of 10. Intuitively without any appeal to mathematics, one would realize this would be a rare outcome and doubt the claim of being a 90% free throw shooter.

The idea of P-Value just makes the notion of rare precise.
It can be shown using something called the binomial probability distribution that if a 90% free throw shooter shot 10 free throws 10,000 times, he/she would only make 5 out of 10 fifteen times!!  This means the P-Value = 0.0015 or 0.15%

So smaller P-Values, constitute stronger proof against a challenged assumption. Not once did I have to mention the word sadistics, I mean statistics.

Many readers have probably heard the famous quote that reflects the contempt that many folks have for statistics:

There are three types of falsehoods: 1. Lies 2. Damned Lies 3. Statistics
Hopefully this explanation of P-Values will lessen your anxiety concerning statistics.



3 comments on “What is a P-Value in Simple English?Add yours →

  1. Don Donigan, of Roswell NM and doubter that humans have caused global warming, proves he may have taken an intro to statistics course when he boldly states correlation does not imply causation. His fondness of Martin Kral gushes in his writing.

    1. Child custody DNA attorney Henry Dickson, who represents himself as a friend of computer programmer Donigan, arrogantly contends that human activity is the cause of global warming in letter to editor of Roswell Daily Record. Another victim of the “post hoc ergo propter hoc” logical fallacy.

      Beware of lawyers who utilize specious reasoning regarding what they perceive to be an “obvious closed case cause/effect”. Also these two friends appear to be showcasing their pseudo intellectual prowess in small town newspaper. True intellectuals do not waste their time with letters to editor in town full insular ignorant people.

      1. This quote by Computer programmer Derek Sivers proves he is not particularly smart: “There are no smart people or stupid people, just people being smart or being stupid.”
        Did any of you listen to or read the alleged interview by Srini Rao where Derek was foisted off as some kind of iconic movement making inspirational guru? Could not find much on Srini Rao who appears maybe to be fictitious interviewer propped up to make a guy who is not famous famous. What do you expect from a guy who puts war paint images of himself in cyberspace?

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