# DBT JRF 2022 — Question 121

Exam: DBT JRF 2022 · Section: B · Topic: Bioinformatics › Data Structures in R/Programming · Difficulty: Medium

## Question

Which one of the following can be considered as a Data Matrix?

## Options

- **A.** Your weight in kg
- **B.** Marks and ages of students in a classroom
- **C.** Name of a pet
- **D.** A list of things to do

## Answer

Option B

## Explanation

Data matrix definition in bioinformatics/statistics: In R programming and bioinformatics: • A matrix is a two-dimensional data structure with ROWS and COLUMNS, where all elements are of the same data type. • A data matrix (data frame) can have multiple variable types in different columns. Examples: • 'Marks AND ages of students': TWO different variables (numeric marks, numeric age) for each student — forms a 2-column matrix/data frame. ✔ This is a DATA MATRIX. • 'A single weight measurement': a scalar (single value), not a matrix. • 'Your name': a single character string, not a matrix. • 'A to-do list': an ordered list (vector), not a matrix. A data matrix requires at least two dimensions with multiple observations (rows) and variables (columns). Answer: 'Marks AND ages of students' forms a data matrix (2-variable, multi-observation).

Source: https://mypyqbuddy.com/questions/which-one-of-the-following-can-be-considered-6a104cd5920734408bc0c788