## Proportions and Ratios

In mathematics and physics, proportionality is a mathematical relation between two quantities. There are two different views of this “mathematical relation.” One is based on ratios, and the other is based on functions.

## Probability

Probability is a way of expressing knowledge or belief that an event will occur or has occurred.

## Basic Logical Reasoning

Deductive logic related to the consistency of statements and beliefs and the validity of arguments.

## Inductive Reasoning

Inductive reasoning is used when generating hypotheses, formulating theories, and discovering relationships.  It is essential for scientific discovery.

## Hypothetical-Deductive Reasoning

Hypothetical-deductive method is a very important method for testing theories or hypotheses and is one of the most basic methods common to all scientific disciplines.

## Hidden Variables

Non-given variables and unobservable relationships between variables are categorized as hidden variables.  Identifying hidden variables is an important step in forming and testing a hypothesis.

## Control of Variables

Control of variables strategy refers to the method used when experimenting with a system that has many variables.  To avoid confounded experiments, all variables but those under consideration must be controlled.

## Correlational Reasoning

In a multi-variable scientific inquiry process, correlation is used to describe the degree of dependence between two variables.

## Conditional Probability

Conditional probability is a difficult topic for students to master. Often counter-intuitive, its central laws are composed of abstract terms and complex equations that do not immediately mesh with subjective intuitions of experience.