I

impossible event

Something that can never happen.

page 11

improper fraction

A fraction with a numerator greater than or equal to the denominator (e.g., ).

independent variable

In an experiment, the variable with values known at the beginning of the experiment. The experimenter often chooses these values before data collection. It is often called the manipulated variable.

inch

Unit used to measure length in the U.S. Customary System. There are 12 inches in a foot.

pages 101, 201, 212

interpolation

Making predictions or estimating values that lie between data points in a set of data.
(See also extrapolation.)

irregular shape

A shape whose sides are not all the same length and whose angles are different measures.

pages 294–295