The Fractionator Principle. The fractionator principle is one of the important concepts used in stereology. The importance of this principle cannot be overlooked. It appears in many different places. Although it looks different depending on how it is used, the principle is the same.
In mathematics, a variable whose value is determined by the value of an independent variable. For example, in the formula for the area of a circle, A = Ïr2, A is the dependent variable, as its value depends on the value of the radius (r). Compare independent variable.
Variable definition. A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable. The letters $x$, $y$, and $z$ are common generic symbols used for variables. Sometimes, we will choose a letter that reminds us of the quantity it represents, such as $t$ for time, $v$ for voltage, or $b$ for bacteria.