what is variables and measurement in research methodology
Variables refer to the characteristics or qualities that can vary or change in research. They are used to measure and study the relationships between different phenomena or concepts. In research methodology, variables are classified into two types:
1. Independent variables (IV): These are the variables that are manipulated or controlled by the researcher. They are the potential causes or influences on the dependent variable. For example, in a study investigating the effect of studying techniques on exam performance, the independent variable would be the different studying techniques applied.
2. Dependent variables (DV): These are the variables that are measured or observed to determine the outcome or result of the study. They are the variables that are influenced or affected by the independent variable(s). In the above example, the dependent variable would be the exam performance of the participants.
Measurement in research methodology refers to the process of assigning numerical values or categories to variables in order to assess and quantify them. It involves identifying appropriate scales or tools to collect data related to the variables. The choice of measurement scale depends on the nature of the variable being studied.
Different measurement scales include:
1. Nominal scale: This scale categorizes variables into different groups or categories. It involves assigning a unique identifier or label to each group without any specific order or numerical value. For example, assigning different categories to participants based on their gender (male, female).
2. Ordinal scale: This scale ranks or orders variables based on their relative position or level. It provides information on the order of categories or values but does not specify the magnitude of differences between them. For example, ranking participants' satisfaction levels on a Likert scale (e.g., very dissatisfied, somewhat dissatisfied, neutral, somewhat satisfied, very satisfied).
3. Interval scale: This scale measures variables on a continuum and allows for the identification of the magnitude of differences between values. It has equal intervals between values but lacks a meaningful zero point. For example, measuring temperature on the Celsius or Fahrenheit scale.
4. Ratio scale: This scale possesses all the characteristics of an interval scale but also has a meaningful zero point that represents the absence of the variable being measured. It allows for the comparison of ratios between values. For example, measuring weight, height, or time.
The appropriate choice of variables and measurement scales is crucial in ensuring the accuracy, reliability, and validity of research findings.