College Geometry, Mathematical Reasoning

Question

Sarah and all of her siblings have brown hair. She concludes that if her parents have another child, he or she will have brown hair. Is this an example of inductive or deductive reasoning?

a) Deductive

b) Inductive

c) Both deductive and inductive

d) Neither deductive nor inductive

Answer 1

From Wikipedia:

Inductive reasoning is a method of reasoning in which the premises are viewed as supplying some evidence of the truth of the conclusion. This is in contrast to deductive reasoning.

Deductive reasoning, also deductive logic, is the process of reasoning from one of more statements to reach a logically certain conclusion.

In English, deductive reasoning is like a proof. One uses one or more principles or axioms to reach a conclusion. But, for inductive reasoning, one looks at a situation and makes an assertion about what happens next.

For your problem, one just looks and sees a bunch of siblings with brown hair and makes an assertion that if the parents have another child, that child would also have brown hair. For deductive reasoning, one might try to give an answer based on logic derived from Genetics, for instance.

Therefore, your answer is b.

Answer 2

I would say that this is an example of inductive reasoning...and one conterexample disproves her logic.