Lec 5 Flashcards
what is a variable?
An image or perception or concept that is able for measurement and its value can change
Also it is the variable that can be measured by any of the four measurement scales and has varying degree of precision. Also they are rational units of analysis that can assume any one of a number of designated sets of values.
What is the difference between the concept and the variable?
The main difference is measurability
Concepts are mental images or perception therefore their meanings vary markedly from individual to another.
While variables are measurable with varying degrees of accuracy, while the concept can’t be measured, however, variables can be subjected to crude/ refined or subjective/objective unit of measurements. Concepts are subjective impressions which means that measuring them would cause problems in comparing responses obtained from responders.
How can we measure a concept?
we should first convert it into a variable and then can be measure even though the degree of precision will differ markedly from a scale to another
1. Nominal 2. Interval 3. Ordinal 4. Ratio
Procedure of converting the concept into variable?
First think of the concept operationalization
Which is the process of identifying the concept indicator
(how the process will be measured?)
The indicator is the reflective criteria of the concept which then will be converted to varisble
What is the difference between quantitative and qualitative research in the area of variables?
The qualitative research usually involved the study of feeling, perceptions, and beliefs. So it impossible to try to make all of them similar as they are different from individual to another , so variable and measurements do jot Carry much significance in this research.
However in quantitative research it emphasis on exploring commonalities in the study population so measurements and variables have significant role.
What are the types of variables?
- The casual relationship
- The study design
- The unit of measurement
What are the types of variables from the viewpoint of change?
1 independent or Change variable: The cause that are responsible for bringing the change to the phenomenon or circumstances
- Dependent or outcome variable: The outcome or change or effect that is brought by the consequence of the change variable
- the variable that affect the link between the cause and effect variable or the extraneous variables: They are other factors from the real life situation may affect the change in the dependent variable, it is not measured in the study , and it affect the relationship between the dependent and independent variables.
- The intervening or the linking variable: Which is sometimes necessary to complete the relationship between the dependent and independent and this relationship cannot be established so is also called the cofounding . The variables will have the assumed effect only in the presence of the intervening variable.
What are the types of variables from the view point of study design?
These are controlled experiments that the researcher or the service provider manipulate or change or control the cause or independent variable which result in having two variables :
- Active variables: The variables that are changed, manipulated or controlled
- Attribute variables: These variables cannot be changed, manipulated, or controlled and they reflect the characteristics of the study population.
What are the types of variables from the viewpoint of unit of measurement?
Categorical variables: Measured by ordinal and nominal scales and they are qualitative.
- constant variables, one category or value, taxi , tree
- dichotomous, has two categories like male female
- polychotomous, has more the two categories like attitude
Continuous variables: Measure by ratio or interval measurement units, they have continuity in their nature, like age income, attitude score
What are the nominal or classificatory scales?
Each subgroup has characteristics which are common to all classified within the subgroup like gender, martial status, color , medical history
What are the ordinal or ranking scales?
It has the characteristics of the nominal scales, as the classified has common properties.
The subgroups are related to each other, arranged ascending or descending. Like weight, income , Likert scale
What are the interval scales?
It has all characteristics of ordinal scale
The unit of measurement is with arbitrary starting and terminal point. Divided into equal intervals or spaced units. Body fat percentage age group
What are the ratio scales?
They have all properties of interval scales
That have fixed starting point like zero
Like age , weight, height
