Which statement best describes a matrix?

• A. A collection of numbers arranged in columns and rows.
• B. A single numeric value summarizing data.
• C. A set of conditions for normal distribution.
• D. A function mapping inputs to probabilities.

Answer: (A)

A matrix is a rectangular grid of numbers organized into rows and columns. Each entry sits at the intersection of a row and a column, and the size is described by rows by columns. This structure is exactly what a matrix is used for in statistics and linear algebra to organize data and perform computations like matrix multiplication or solving systems of equations. A single numeric value is a scalar, not a grid; a set of conditions for normal distribution describes assumptions about data rather than a grid; a function mapping inputs to probabilities describes a probability model rather than a grid. So the description that a matrix is a collection of numbers arranged in columns and rows is the best fit.