A short-hand way of writing very large or very small numbers. The notation consists of a decimal number between 1 and 10 multiplied by an integral power of 10. For example, 47,300 = 4.73 x 104 ; 0.000000021 = 2.1 x 10-8.

The relationship between two objects that have exactly the same shape but not necessarily the same size.

Carrying out extensive data collection with a simple, safe, inexpensive, easy-to-duplicate event that has essentially the same characteristics as another event which is of actual interest to an investigator. For example, suppose one wanted to gather data about the actual order of birth of boys and girls in families with five children. (e.g., BBGBG is one possibility) Rather than wait for five children to be born to a single family, or identifying families that already have five children, one could simulate births by repeatedly tossing a coin five times. Heads vs. tails has about the same chance of happening as a boy vs. a girl being born.

A single number representation of the characteristics of a set of data. Usually given by measures of central tendency and measures of dispersion (spread).

A figure has symmetry if it has parts that correspond with each other in terms of size, form, and arrangement. For example, a figure with line (or mirror) symmetry has two halves which match each other perfectly if the figure is folded along its line of symmetry.

A quantity that may assume any one of a set of values. Usually represented in algebraic notation by the use of a letter. In the equation