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Inductive Reasoning

MODULE M

INDUCTIVE REASONING

HINT SHEET

INDUCTION moves from a limited observation to a probable conclusion.

This reasoning process involves three steps: 1) making a LIMITED OBSERVATION, 2) INFERRING the broader implications of the observation, and 3) drawing a PROBABLE CONCLUSION.

GENERALIZATION: A conclusion which covers a number of particular cases, not all of which have been directly observed.

UNIVERSAL GENERALIZATIONS (ALL-NONE) relate characteristics to the entire population.

QUALIFIED GENERALIZATIONS (MOST-FEW) relate characteristics to a part of the population which is defined descriptively.

STATISTICAL GENERALIZATIONS (3/4-75%) relate characteristics to a part of the population which is defined as a ratio.

CONFUSED CONCLUSIONS are conclusions which have a low probability (or no probability) of being true because they are

based on a numerically insignificant sample,

based on a nonrepresentative sample, and/or

based on an incorrect analysis of the sample.

CAUSE/EFFECT ANALYSIS is a reasoning process for determining what brought about an observable conclusion.

METHOD OF AGREEMENT determines the cause by listing all of the possible factors, choosing the one factor which all the cases have in common, and naming that factor the cause.

METHOD OF DIFFERENCE determines the cause by listing possible factors, eliminating all factors that also occur in cases where the effect is not observed, and naming the factor that remains the cause.

JOINT METHOD is a method of finding the cause that combines the methods of agreement and difference. First, by the method of agreement, the common factors are found. Then, by the method of difference, all common factors but one are eliminated.

METHOD OF VARIATIONS is a method where the cause is BOTH IDENTIFIED and ITS STRENGTH DETERMINED by noticing variations in the effect it produces.

METHOD OF RESIDUES is a method where a list of POSSIBLE CAUSES is made first; then by testing or observation, all causes but one are eliminated. This residual cause is named as the actual cause.

An ANALOGY points out a correspondence between things that may not otherwise be alike in order to show a similarity between them.

An INDUCTIVE ANALOGY compares two things or events of different types. If it is found that the two types are alike in some respects, then, one may infer that they may also be alike in other respects as well.

IRRELEVANCE refers to something not connected with the matter at hand.