variation in phenotypic traits in which types are grouped into discrete categories with few or no intermediate phenotypes. Compare continuous variation.
variation in phenotypic traits such as body weight or height in which a series of types are distributed on a continuum rather than grouped into discrete categories. Compare discontinuous variation.
Continuous and Discontinuous variables: Variables have different properties and to these properties we assign numerical values. If the values of a variable can be divided into fractions then we call it a continuous variable. Such a variable can take infinite number of values. Income, temperature, age, or a test score are examples of continuous variables. These variables may take on values within a given range or, in some cases, an infinite set. Any variable that has a limited number of distinct values and which cannot be divided into fractions, is a discontinuous variable. Such a variable is also called as categorical variable or classificatory variable, or discrete variable. Some variables have only two values, reflecting the presence or absence of a property: Employed-unemployed or male-female have two values. These variables are referred to as dichotomous. There are others that can take added categories such as the demographic variables of race, religion. All such variables that produce data that fit into categories are said to be discrete/categorical/classificatory, since only certain values are possible. An automotive variable, for example, where "Chevrolet" is assigned a 5 and "Honda" is assigned a 6, provides no option for a 5.5 (i.e. The values cannot be divided into fractions).