Section 1.4: Variables

Fundamentals of Social Statistics by Adam J. McKee

Science attempts to discover patterns in a reality that often seems chaotic.  Even from the most ancient times, people have attempted to describe patterns in the world around them.  Ancient peoples noted the changes of the season, changes in the phase of the moon, changes in the tide.  They also noted that these things (and many others) changed in a regular pattern.  In the sciences, things that change and have different values from time to time or from person to person are called variables.

A variable is a characteristic, attribute, or condition that has different values for different individuals.

In research and data analysis, variables play a crucial role as they are the attributes or conditions that can differ across subjects or settings. These attributes can vary from personal characteristics like weight, gender, religious affiliation, and political beliefs, to situational factors like the time of day an experiment is conducted. Understanding the nature and types of variables is essential for any research project because they form the basis of your observations and ultimately affect the conclusions you can draw. For example, if a study aims to understand the correlation between sleep patterns and productivity, variables might include the amount of sleep, time of day, and even the person’s age or occupation.

Measurement and Notation of Variables

When measuring variables, it’s common practice for researchers to assign each variable a symbolic notation, often using letters like X or Y. If a study involves two variables, X might denote the first variable, such as hours of sleep, and Y might denote the second variable, like productivity levels. This shorthand not only streamlines data notation but also simplifies the representation of relationships between variables. For instance, in statistical modeling or equations, you may encounter expressions like “Y = f(X)” to describe how one variable (Y) is influenced by another (X).

Data Organization: Rows and Columns

In a dataset, a variable often corresponds to a column of data, a convention that arises from organizing individual data points in rows. For instance, if you’re looking at a spreadsheet where each row represents data for a single individual, columns might represent variables like age, income, or education level. The use of columns for variables and rows for individual data points is an established norm in statistics and data science, making it easier to perform analyses using statistical software or spreadsheet programs like Excel. When all variables are considered together, they constitute the comprehensive dataset that is the subject of the research project.

The Concept of Constants

In contrast to variables, a constant is a value that remains unchanged across different individuals or conditions. For example, in an experiment studying the effects of a specific drug dosage on blood pressure, the drug dosage might be held constant for all participants. Constants serve an essential role in research, particularly in experimental design, where they ensure that the observed effects are indeed due to the variables being studied, not other extraneous factors.

Constants and Scientific Control

The concept of a constant is closely related to the idea of control in scientific research, a topic we will delve deeper into in subsequent sections. In social science research, control entails keeping certain variables or conditions unchanged to better isolate the effect of the variable being examined. By maintaining these constants, researchers can more confidently attribute observed changes to the variable they are focusing on rather than to other extraneous factors.

For example, if you are investigating the impact of educational interventions on high school student’s academic performance, you might hold constant other variables like socio-economic status or baseline academic ability to ensure that observed changes in performance are indeed due to the intervention. In sum, grasping the roles of variables and constants is critical for the credibility and reliability of research, particularly in social sciences, where multiple factors often interact in complex ways.

A constant is an attribute of a person or a condition that does not change from person to person but stays the same for every individual.

Attributes of Variables

An attribute is a specific value of a variable.  For example, the variable gender has two attributes: male and female.  Attributes are commonly referred to as a level of the variable.  It is important to note the difference between the variable and its value for a particular individual.  For example, the variable gender can take on two different levels:  Male and female.

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Last Modified:  09/06/2023

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