Types of Variables in Research

Comprehensive practice flashcards covering the definitions, types, and measurement scales of variables used in research as described in the lecture notes.

How is an 'observation' defined in research data collection?

Each person or thing we collect data on is called an observation; in research, these are usually people or subjects.

What is the difference between a 'constant' and a 'variable'?

A constant is a characteristic that is the same for every member of a group, while a variable is a characteristic that differs for group members.

What are independent variables?

Independent variables are variables that are manipulated, controlled, or changed; they represent the presumed or possible cause in a study.

What are dependent variables?

Dependent variables are the outcome variables for which statistics are calculated; they are influenced or affected by the independent variable (presumed results or effect).

In a study investigating the effect of revision time and intelligence on test performance, what are the variables?

The Dependent Variable is the Test Mark (measured from $0$ to $100$), and the Independent Variables are Revision time (hours) and Intelligence (IQ score).

In a study of teacher-student classroom interaction at different levels of schooling, what are the independent and dependent variables?

The Independent Variable is the Level of schooling (primary, upper primary, secondary, and junior college). The Dependent Variable is the score on a classroom observation inventory measuring teacher-student interaction.

In a study of professional attitudes of secondary school teachers by gender, what are the independent and dependent variables?

The Independent Variable is the Gender of the teacher (male, female). The Dependent Variable is the score on a professional attitude inventory.

What is a moderator variable?

A special type of independent variable that modifies the relationship between the independent variable and the dependent variable under different conditions.

In the example of library facilities ($X$) and student performance ($Y$), what acts as the moderating variable?

The interest and inclination of the students to use the library.

What is the difference between quantitative and qualitative variables?

Quantitative variables exist along a continuum from low to high (e.g., height, test scores). Qualitative variables (categorical) express differences in kind or category rather than amount (e.g., gender, religion).

What is a nominal scale?

The simplest measurement scale used for labeling variables into distinct classifications without quantitative value or order (e.g., gender, political preferences).

What is an ordinal scale?

A scale used to depict the order of variables where the rank matters, but the exact difference between the variables is not known (e.g., satisfaction levels, educational attainment).

What are the characteristics of an interval scale?

A numerical scale where the order is known and the differences between variables are constant and computable, but there is no true zero (e.g., calendar years, Likert scale).

What distinguishes a ratio scale from an interval scale?

A ratio scale possesses all the properties of nominal, ordinal, and interval scales, but also includes a value of absolute zero (e.g., weight in kilograms, height).

What is a continuous variable?

A variable whose values can be divided into fractions and can take an infinite number of values within a range (e.g., income, temperature, age).

What is a discontinuous variable (also known as discrete or categorical)?

A variable that has a limited number of distinct values and cannot be divided into fractions.

What is the difference between dichotomous and trichotomous variables?

Dichotomous variables have only two values (e.g., male/female, alive/dead). Trichotomous variables have three categories (e.g., urban, semi-urban, and rural).

What are demographic variables?

Characteristics or attributes of subjects collected to describe the sample, such as age, gender, occupation, marital status, and income.

What are extraneous variables?

Variables that may affect research outcomes but have not been adequately considered in the study; they can affect the relationship among study variables.

What is the difference between confounding and intervening variables?

Confounding variables are extraneous variables not recognized until the study is in process or recognized but uncontrollable. Intervening variables are external variables that influence the relationship between research variables even if the researcher cannot see them.

What is a control variable?

A variable that is deliberately held constant, neutralized, or eliminated during a study to prevent it from having a biasing effect on other variables.