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Scaling
 

Scaling

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    Scaling Scaling Presentation Transcript

    • Meaning of Measurement andScalingMeasurement: The term ‘measurement’means assigning numbers or some other symbolsto the characteristics of certain objects. Whennumbers are used, the researcher must have a rulefor assigning a number to an observation in a waythat provides an accurate description.Scaling: Scaling is an extension ofmeasurement. Scaling involves creating acontinuum on which measurements on objectsare located.SLIDE 7-1
    • Types of Measurement ScaleNominal scale: This is the lowest level of measurement. Here,numbers are assigned for the purpose of identification of the objects.Any object which is assigned a higher number is in no way superior tothe one which is assigned a lower number.Example:• Are you married?(a) Yes (b) NoMarried person may be assigned a no. 1.Unmarried person may be assigned a no. 2.The assigned numbers cannot be added, subtracted, multiplied ordivided. The only arithmetic operations that can be carried out arethe count of each category. Therefore, a frequency distribution tablecan be prepared for the nominal scale variables and mode of thedistribution can be worked out.SLIDE 7-2
    • Types of Measurement ScaleOrdinal scale: This is the next higher level ofmeasurement. One of the limitations of the nominalscale measurements is that we cannot say whetherthe assigned number to an object is higher or lowerthan the one assigned to another option. Theordinal scale measurement takes care of thislimitation. An ordinal scale measurement tellswhether an object has more or less of characteristicsthan some other objects.SLIDE 7-3
    • Types of Measurement ScaleSLIDE 7-4Example:Rank the following attributes while choosing a restaurant fordinner. The most important attribute may be ranked one, the nextimportant may be assigned a rank of 2 and so on.In the ordinal scale, theassigned ranks cannot beadded, multiplied, subtracted ordivided. One can computemedian, percentiles andquartiles of the distribution. Theother major statistical analysiswhich can be carried out is therank order correlationcoefficient, sign test.
    • Types of Measurement ScaleInterval scale: The interval scale measurement is the next higher level ofmeasurement.It takes care of the limitation of the ordinal scale measurement where thedifference between the score on the ordinal scale does not have anymeaningful interpretation.In the interval scale the difference of the score on the scale hasmeaningful interpretation.It is assumed that the respondent is able to answer the questions on acontinuum scale.The mathematical form of the data on the interval scale may be written asY = a + b X where a ≠ 0Ratio of the score on this scale does not have a meaningful interpretation.SLIDE 7-5
    • Types of Measurement ScaleSLIDE 7-6Example:The numbers on this scale can be added,subtracted, multiplied or divided. One cancompute arithmetic mean, standard deviation,correlation coefficient and conduct a t-test, Z-test, regression analysis and factor analysis.
    • Types of Measurement ScaleRatio scale: This is the highest level of measurement and takes careof the limitations of the interval scale measurement, where the ratioof the measurements on the scale does not have a meaningfulinterpretation.The mathematical form of the ratio scale data is given by Y = b X.In ratio scale, there is a natural zero (origin).Example:How many chemist shops are there in your locality?How many students are there in the MBA programme at IIFT?All mathematical and statistical operations can be carried out usingthe ratio scale data.SLIDE 7-7
    • Definition of AttitudeAn attitude is viewed as an enduring dispositionto respond consistently in a given manner tovarious aspects of the world, including persons,events and objects.Components of Attitude:Cognitive componentAffective componentIntention or action componentSLIDE 7-8
    • Classification of ScalesSingle item vs multiple item scale:In the single item scale, there is only one item tomeasure a given construct.In multiple item scale, there are many items that playa role in forming the underlying construct that theresearcher is trying to measure. This is because each ofthe item forms some part of the construct which theresearcher is trying to measure.SLIDE 7-9
    • Classification of ScalesComparative vs non-comparative scalesSLIDE 7-10
    • Classification of Scales Comparative scales – In comparative scales it is assumed thatrespondents make use of a standard frame of reference before answeringthe question.Example:-SLIDE 7-11Classification of Scales
    • Classification of ScalesFormats of Comparative Scales –Paired comparison scalesRank order scaleConstant sum rating scaleQ-sort techniqueNon-Comparative Scales – In the non-comparativescales, the respondents do not make use of any frameof reference before answering the questions.
    • SLIDE 7-13Classification of ScalesGraphic Rating Scale – This is a continuous scale and therespondent is asked to tick his preference on a graph.Examples:Non-comparative scaleGraphic rating scale Itemized rating scale
    • SLIDE 7-14Classification of ScalesPlease put a tick mark (•) on the following line to indicate yourpreference for fast food.Alternative Presentation of Graphic Rating Scale –Please indicate how much do you like fast food by pointing to theface that best shows your attitude and taste. If you do not prefer itat all, you would point to face one. In case you prefer it the most,you would point to face seven.
    • SLIDE 7-16Classification of ScalesExamples of Itemized Rating Scales:Likert scale The respondents are given a certain number of items (statements) on whichthey are asked to express their degree of agreement/disagreement. This is also called a summated scale because the scores on individual items canbe added together to produce a total score for the respondent. An assumption of the Likert scale is that each of the items (statements)measures some aspect of a single common factor, otherwise the scores on theitems cannot legitimately be summed up. In a typical research study, there are generally 25 to 30 items on a Likert scale.
    • SLIDE 7-17Classification of ScalesExample of a Likert Scale:
    • SLIDE 7-18Classification of ScalesSemantic Differential ScaleThis scale is widely used to compare the images of competingbrands, companies or services.Here the respondent is required to rate each attitude or objecton a number of five-or seven-point rating scales.This scale is bounded at each end by bipolar adjectives orphrases.The difference between Likert and Semantic differential scale isthat in Likert scale, a number of statements (items) arepresented to the respondents to express their degree ofagreement/disagreement. However, in the semantic differentialscale, bipolar adjectives or phrases are used.
    • SLIDE 7-20Classification of ScalesExample of Semantic Differential Scale: (Pictorial Profile)
    • SLIDE 7-21Classification of ScalesStapel Scale
    • SLIDE 7-23Criteria for good measurementReliabilityReliability is concerned with consistency, accuracy andpredictability of the scale.Methods to measures ReliabilityTest–retest reliabilitySplit-half reliabilityCronbach’s Alpha
    • SLIDE 7-24Criteria for good measurementValidityThe validity of a scale refers to the question whether we are measuring what wewant to measure.Different ways to measure ValidityContent validityConcurrent validityPredictive validitySensitivitySensitivity refers to an instrument’s ability to accurately measure the variabilityin a concept.