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Introduction : Variables
- What are independent and dependent variables and the difference between them?
- What are discrete and continuous variables and the difference between them?
- What are qualitative and quantitative variables and the difference between them?
Independent and dependent variables
Variables refer to an attribute which gives description about a person, thing, place, idea etc, and itsí value differ or vary. Experimenters consider variables at the time of conducting the research. In an experiment, the variable which varies or the variable which is manipulated by the researcher is termed as the independent variable. Whereas, the measured response in the experiment is called the dependent variable. Presumed cause is explained through independent variables, and the presumed effect is explained through dependent variables. So, the independent variables acts as the antecedent, and the dependent variable works as the consequent. It should be remembered that, in an experiment, the dependent variable is not manipulated,the dependent variable is only observed and the variation is observed and measured.
- Example 1: To test, whether there exists a statistical significant difference in the mean scores of math between the students who attain training session in an institution and the students who do not attain it. So, now you need to decide which is the independent variable and which is the dependent one. So, here the independent variable is attending the training session of the institution, and the dependent variable is the mean score.
- Example 2: Let us consider a study of the effect of different doses of a particular drug on the severity of symptoms of a disease. Now, the researcher who is performing this experiment will consider the different doses as the independent variable, and the intensity of symptoms as the dependent one, after which conclusions are made.
- Example 3: In a study, the amount of color which is removed from the sample of beet-root at varying temperatures needs to be measured. Here, the temperature is the independent variable and the amount of color removed will be the dependent variable.
What are the levels of an Independent Variable?
When, in an experiment, a comparison is made between an experimental treatment and the control treatment, and then there arise two levels of an independent variable. For example when you need to compare four types of foods, then there occurs 4 levels of the independent variable (type of food). So, the number of levels of the independent variable refers to the number of conditions of the experiment under consideration.
Qualitative and Quantitative Variables
There are differences between qualitative and quantitative variables. In Statistics there are two kinds of variables- the qualitative and the quantitative.
A qualitative variable is that kind of variable which is not measurable; these are the variables that are expressed in terms of their attributes or qualitative character. For example the grades obtained by students in a test or color of flowers represent qualitative variables.
On the other hand, a quantitative variable is the one which can be calculated and is finite. This kind of variable is measured on a ratio, ordinal or interval scale. Thus, quantitative character is measurable and is countable. For example, the weight of students in a school, ages of boys, family size, the marks of students in class, etc.
Discrete and Continuous Variables
Variables can be classified into two main types, namely -
- Discrete variable
- Continuous variable.
Discrete variables are quantitative character that can take certain isolated values only in its range of variation. The number of students in different colleges, the size of families of some locality, proportion of males in a group of 10 persons.etc. are examples of discrete variables.
Continuous variable is a variable that can assume any value within its range of variation. The weights of individuals, the marks obtained by students in an examination, income of different persons, etc. belong to this category of variables.
Statistical help and online statistics help provided by us will thus help you to learn the proper use and various aspects of statistics.