A fallacy of defective induction reaches a conclusion from weak premises. Unlike fallacies of relevance, in fallacies of defective induction, the premises are related to the conclusions yet only weakly buttress the conclusions. A faulty generalization is thus produced. This inductive fallacy is any of several errors of inductive inference

Inductive reasoning

Inductive reasoning, also known as induction or inductive logic, is a kind of reasoning that constructs or evaluates propositions that are abstractions of observations. It is commonly construed as a form of reasoning that makes generalizations based on individual instances...

.

Logic

The proportion Q of the sample has attribute A.

Therefore, the proportion Q of the population has attribute A.

Such a generalization proceeds from a premise about a sample

Sample (statistics)

In statistics, a sample is a subset of a population. Typically, the population is very large, making a census or a complete enumeration of all the values in the population impractical or impossible. The sample represents a subset of manageable size...

 to a conclusion about the population

Statistical population

A statistical population is a set of entities concerning which statistical inferences are to be drawn, often based on a random sample taken from the population. For example, if we were interested in generalizations about crows, then we would describe the set of crows that is of interest...

.

Faulty generalization is a mode of thinking that takes knowledge from one group's or person's experiences and incorrectly extends it to another.

Inductive fallacies

• Hasty generalization
  Hasty generalization
  Hasty generalization is a logical fallacy of faulty generalization by reaching an inductive generalization based on insufficient evidence essentially making a hasty conclusion without considering all of the variables...
  
   is the fallacy of examining just one or very few examples or studying a single case, and generalizing that to be representative of the whole class of objects or phenomena.
• The opposite, Slothful induction
  Slothful induction
  A slothful induction is a fallacy in which an inductive argument is denied its proper conclusion, despite strong evidence for inference. The opposite fallacy is the hasty generalization.-Examples:-External links:*...
  
  , is the fallacy of denying the logical conclusion of an inductive argument, dismissing an effect as "just a coincidence" when it is very likely not to be.
• The overwhelming exception
  Overwhelming exception
  An overwhelming exception is a logical fallacy similar to a hasty generalization. It is a generalization that is accurate, but comes with one or more qualifications which eliminate so many cases that what remains is much less impressive than the initial statement might have led one to...
  
   is related to the hasty generalization, but working from the other end. It is a generalization which is accurate, but tags on a qualification which eliminates enough cases (as exceptions); that what remains is much less impressive than what the original statement might have led one to assume.
• Biased sample
  Biased sample
  In statistics, sampling bias is when a sample is collected in such a way that some members of the intended population are less likely to be included than others. It results in a biased sample, a non-random sample of a population in which all individuals, or instances, were not equally likely to...
  
   – When the above happen because of (personal) bias of the sampling entity.
• Misleading vividness
  Misleading vividness
  Misleading vividness is a term that can be applied to anecdotal evidence describing an occurrence, even if it is an exceptional occurrence, with sufficient detail to permit hasty generalizations about the occurrence...
  
   is a kind of hasty generalization that appeals to the senses.
• Statistical special pleading
  Special pleading
  Special pleading is a form of spurious argumentation where a position in a dispute introduces favorable details or excludes unfavorable details by alleging a need to apply additional considerations without proper criticism of these considerations themselves. Essentially, this involves someone...
  
   occurs when the interpretation of the relevant statistic is "massaged" by looking for ways to reclassify or requantify data from one portion of results, but not applying the same scrutiny to other categories.

See also

• Association fallacy
  Association fallacy
  An association fallacy is an inductive informal fallacy of the type hasty generalization or red herring which asserts that qualities of one thing are inherently qualities of another, merely by an irrelevant association. The two types are sometimes referred to as guilt by association and honor by...
  
  
• Cherry picking (fallacy)
• Package-deal fallacy
  Package-deal fallacy
  The logical fallacy of the package deal consists of assuming that things often grouped together by tradition or culture must always be grouped that way....
  
  
• Straw man
  Straw man
  A straw man is a component of an argument and is an informal fallacy based on misrepresentation of an opponent's position, twisting his words or by means of [false] assumptions...