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# Chapter 5_variable

## on Jan 12, 2014

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• Before moving to the third category of measurement, let me present to you all about the types of measurement scale. <br />

## Chapter 5_variablePresentation Transcript

• Chapter 5: identifying variables Presented by Mr. Soeung Sopha, soeungsopha@yahoo.com 1
• Content  Definition of Variable  Concept VS. Variable  Concept, Indicator and Variable  Types of Variable  Types of Measurement Scale 2
• Think of these This program is effective. . This program is effective This program is not effective. . This program is not effective This is aawaste of time. . This is waste of time This product is not doing This product is not doing well. . well 3
• Variable?  An image, perception or concept that is Capable of measurement – capable of taking on different values – is called Variable.  A concept that can be measured is called a Variable.  A variable is a property that takes on different values.  A variable is a symbol to which numerals or values are attached.  A variable is defined as rational units of analysis that can assume any one of a number of designated sets of values.  A concept that can be measured on any one of four types measurement scale, which have varying degrees of precision in measurement is called a Variable.  Some variables are incapable to directly measure like feeling, sentiment.Thus, it cab be vary from person to person. 4
• Concept vs. variable  Concept are mental images or perception and therefore their meanings can be vary markedly from person to person.  A concept cannot be measured  Variables are measurable with varying degrees of accuracy.  A variable can be subjected to measurement by crude/refined or subject/objective units of measurement.  Measurability is the main difference between a concept and a variable. 5
• Main Difference Concept Variable Subjective impression No uniformity as to its understanding among different people Measurable though the degree of precision varies from scale to scale and from variable to variable. e.g. Attitude – subjective, Income - Objective As such cannot be measured See Table 5.1_page 57 6
• Concept, Indicator & variable  If you use Concept in your study, you need to think of operationalization – how it is measured.  To operationalize, you first have to think of Indicators which then can be converted into variables.  Indicator is a set of criteria reflective of the concept When you use aaconcept When you use concept RICH in your study, how RICH in your study, how can you measure ififaa can you measure person RICH? person RICH? 7
• But!! ???? But!! ???? Income Income Assets Assets dollars dollars Concept Concept Variable Variable House, House, cows, cows, cars …. cars …. Convert its Convert its values to \$ values to \$ \$ \$ Easy!! Easy!! Add up !! Add up !! Rich or Rich or Poor? Poor? Add up for Add up for average average See Table 5.2_page 58 8
• Types of Variable All relationship Btw cause and effect need it. Intervening/co Intervening/co nfounding nfounding Variables Variables Are not measured in the study, may increase or decrease the strength of relationship Extraneous Extraneous Variables Variables Connecting or Linking Variables Cause Cause Effect Effect Change variables Independent Independent Variables Variables Outcome Variables Variables that affect the relationship Cause & Effect Research Dependent Dependent Variables Variables See examples at pages 61, 62 & 63 9
• Quasiexperiment Controlled experiment Ex post facto - Different teaching methods - Experimental intervention - Program service … Active Variables Active Variables Can be manipulated, changed or controlled Attributive Attributive Variables Variables Can’t be manipulated It reflects the characteristics of the study population 10
• Types of Measurement scale Categorical Variables Categorical Variables Gender: Male (1) Female (2) 1- Constant 1- Constant 2- Dichotomous 2- Dichotomous 3- Polytomous 3- Polytomous Below average (1) Average (2) Above average (3) It doesn’t mean 1 < 2 It means 1 < 2 < 3 Mathematical operation can be done Mathematical operation cannot be done Person aged 40 is twice older than 20 Continuous Variables Continuous Variables See Table 5.4_page 11
• 1- Constant: has only one value 2- Dichotomous: has two values 3- Polytomous: has more than two values Categorical Qualitative They both use They both use Nominal and ordinal Nominal and ordinal measurement scales measurement scales Continuous Quantitative When we develop this category into continuous scale Income of people: Income of people: In dollar In dollar They both use They both use Interval and Ratio Interval and Ratio measurement scales measurement scales We want to measure as We want to measure as Low, Middle and High income Low, Middle and High income 12