Jump to content

Process of elimination: Difference between revisions

From Wikipedia, the free encyclopedia
Content deleted Content added
In education testing: "Luck"? Are you serious?
Tags: Mobile edit Mobile web edit
See also: added link to fun logic game which can be played using a process of elimination
 
(31 intermediate revisions by 22 users not shown)
Line 1: Line 1:
'''Process of elimination''' is a method to identify an entity of interest among several ones by excluding all other entities.
{{Short description|Logical method to identify an entity of interest among several ones by excluding all other entities}}
{{other uses|Elimination (disambiguation)}}
'''Process of elimination''' is a [[logic]]al method to identify an entity of interest among several ones by excluding all other entities. In [[educational testing]], it is a process of deleting options whereby the possibility of an option being correct is close to zero or significantly lower compared to other options. This version of the process does not guarantee success, even if only one option remains, since it eliminates possibilities merely as improbable. The process of elimination can only narrow the possibilities down, and thus, if the correct option is not amongst the known options, it will not arrive at the truth.


==Method==
==In education testing==
In [[educational testing]], the ''process of elimination'' is process of deleting options whereby the possibility of option being correct is close to zero or significantly lower compared to other options. The process does not guarantee success, even if only 1 option remains.


The method of elimination is [[iterative algorithm|iterative]]. One looks at the answers, determines that several answers are unfit, eliminates these, and repeats, until one cannot eliminate any more. This iteration is most effectively applied when there is [[logic]]al structure between the answers – that is to say, when by eliminating an answer one can eliminate several others. In this case one can find the answers which one cannot eliminate by eliminating any other answers and test them alone – the others are eliminated as a [[logical consequence]]; this is the idea behind optimizations for computerized searches when the input is sorted – as, for instance, in [[binary search algorithm|binary search]].
===Method===
The method of elimination is [[iterative algorithm|iterative]]. One looks at the answers, determines that several answers are unfit, eliminates these, and repeats, until one cannot eliminate any more. This iteration is most effectively applied when there is [[logic]]al structure between the answers – that is to say, when by eliminating an answer one can eliminate several others. In this case one can find the answers which one cannot eliminate by eliminating any other answers and test them alone – the others are eliminated as a [[logical consequence]]. (This is the idea behind optimizations for computerized searches when the input is sorted – as, for instance, in [[binary search algorithm|binary search]]).


In order for the method to work it is necessary to list all possible, even improbable, possibilities. Any omissions render the method invalid as a [[logic]]al method.
===Application===
{{Howto|date=January 2011}}
Here are two questions of one sort, to illustrate how this tactic is applied. In the first, elimination produces an answer almost at once – if you know how to go at it; in the other, there is no way around it – you must try every answer.


==Medicine==
By which of the following is the number 2135 [[divisibility|divisible]]: 2, 3, 4, 15, 7? Since (see [[divisibility rule]] for a refresher) 2135 is not divisible by 2, it is not divisible by 4; since 2 + 1 + 3 + 5 = 11 and it is not divisible by 3 (11 is not divisible by 3), it is not divisible by 15. Then only 7 is left; and, indeed: 305 times 7 is 2135.
A process of elimination can be used to reach a [[diagnosis of exclusion]]. It is an underlying method in performing a [[differential diagnosis]].

Note that, if we had a number divisible by 2 but not by 4 (and not divisible by 7), then testing 2 would give us the answer at once. It is always worth testing answers whose exclusion eliminates possibilities, for then, as long as there is only one answer, these possibilities will not need to be tested at all; in effect we incorporate all the information found ''between our answers'' and reduce the set.

Now by which of the following is the number above divisible: 2, 3, 7, 11, 13? All of these numbers are prime; to eliminate one of them furnishes no information about the rest. We must test them all in order to find the answer.

==In medicine==
A process of elimination can be used to reach a [[diagnosis of exclusion]].

It is also an underlying method in performing a [[differential diagnosis]].


==See also==
==See also==
* [[Disjunctive syllogism]]
*[[Troubleshooting]]
* [[Law of excluded middle]]
* [[Philosophical razor]]
* [[Troubleshooting]]
* [[twenty questions]] Spoken word game using logic.


==References==
==References==
* Richard L. Burden, J. Douglas Faires (2000). ''Numerical Analysis'', 7th ed. Brooks/Cole. ISBN 0-534-38216-9.
* Richard L. Burden, J. Douglas Faires (2000). ''Numerical Analysis'', 7th ed. Brooks/Cole. {{ISBN|0-534-38216-9}}.


[[Category:Philosophical logic]]
[[Category:Philosophical logic]]
[[Category:Philosophical methodology]]
[[Category:Philosophical methodology]]



{{philo-stub}}
{{philo-stub}}
{{logic-stub}}

Latest revision as of 07:00, 16 November 2023

Process of elimination is a logical method to identify an entity of interest among several ones by excluding all other entities. In educational testing, it is a process of deleting options whereby the possibility of an option being correct is close to zero or significantly lower compared to other options. This version of the process does not guarantee success, even if only one option remains, since it eliminates possibilities merely as improbable. The process of elimination can only narrow the possibilities down, and thus, if the correct option is not amongst the known options, it will not arrive at the truth.

Method

[edit]

The method of elimination is iterative. One looks at the answers, determines that several answers are unfit, eliminates these, and repeats, until one cannot eliminate any more. This iteration is most effectively applied when there is logical structure between the answers – that is to say, when by eliminating an answer one can eliminate several others. In this case one can find the answers which one cannot eliminate by eliminating any other answers and test them alone – the others are eliminated as a logical consequence; this is the idea behind optimizations for computerized searches when the input is sorted – as, for instance, in binary search.

In order for the method to work it is necessary to list all possible, even improbable, possibilities. Any omissions render the method invalid as a logical method.

Medicine

[edit]

A process of elimination can be used to reach a diagnosis of exclusion. It is an underlying method in performing a differential diagnosis.

See also

[edit]

References

[edit]
  • Richard L. Burden, J. Douglas Faires (2000). Numerical Analysis, 7th ed. Brooks/Cole. ISBN 0-534-38216-9.