Quartiles.
The 25th, 50th and 75th percentile points. (See definition of Percentile.)
Range (of a set of data).
The numerical difference between the largest and smallest values in a set of data.
Rational number.
A number that can be expressed as the ratio, or quotient, of two integers, a/b, provided b 0. Rational numbers can be expressed as common fractions or decimals, such as 3/5 or 0.6. Finite decimals, repeating decimals, mixed numbers and whole numbers are all rational numbers. Nonrepeating decimals cannot be expressed in this way, and are said to be irrational.
Real numbers.
All the numbers which can be expressed as decimals.
Realworld problems.
Quantitative and spatial problems that arise from a wide variety of human experiences, applications to careers. These do not have to be highly complex ones and can include such things as making change, figuring sale prices, or comparing payment plans.
Rectangular coordinate system.
This system uses two (for a plane) or three (for space) mutually perpendicular lines (called coordinate axes) and their point of intersection (called the origin) as the frame of reference. Specific locations are described by ordered pairs or triples (called coordinates) that indicate distance from the origin along lines that are parallel to the coordinate axes.
