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Transcript of Ch 1_MDA_6e_PH
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LEARN I NG OBJE CTIV ES:LEARN I NG OBJE CTIV ES:
U pon completing this chapter, you should be able to do theU pon completing this chapter, you should be able to do thefollowing:following:
1.1. Ex plain what multivariate analysis is and when its application Ex plain what multivariate analysis is and when its application is appropriate.is appropriate.
2.2. Define and discuss the specific techniques included in Define and discuss the specific techniques included in multivariate analysis.multivariate analysis.
3.3. Determine which multivariate technique is appropriate for aDetermine which multivariate technique is appropriate for aspecific research problem.specific research problem.
4.4. Discuss the nature of measurement scales and their Discuss the nature of measurement scales and their relationship to multivariate techniques.relationship to multivariate techniques.
5.5. Describe the conceptual and statistical issues inherent in Describe the conceptual and statistical issues inherent in multivariate analyses.multivariate analyses.
Chapter 1: Introduction Chapter 1: Introduction
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W hat is it? Multivariate Data Analysis = all W hat is it? Multivariate Data Analysis = all statistical methods that simultaneously analyzestatistical methods that simultaneously analyzemultiple measurements on each individual or multiple measurements on each individual or object under investigation.object under investigation.
W hy use it? W hy use it?
Measurement Measurement
Ex planation & Prediction Ex planation & Prediction
Hypothesis TestingHypothesis Testing
W hat is Multivariate Analysis? W hat is Multivariate Analysis?
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The VariateThe Variate
Measurement S cales Measurement S cales N onmetric N onmetric
Metric Metric
Multivariate Measurement Multivariate Measurement
Measurement E rror Measurement E rror
Types of Techniques Types of Techniques
Basic Concepts of Multivariate AnalysisBasic Concepts of Multivariate Analysis
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The variate is a linear combination of variables withThe variate is a linear combination of variables withempirically determined weights.empirically determined weights.
W eights are determined to best achieve theW eights are determined to best achieve the
objective of the specific multivariate technique.objective of the specific multivariate technique. Variate equation : (Y) =Variate equation : (Y) = W 1W 1 X X 11 ++ W 2 W 2 X X 2 2 + . . . ++ . . . + W n W n X X n n
E ach respondent has a variate value (Y).E ach respondent has a variate value (Y).
The Y The Y valuevalue is ais a linear combination linear combination of the entireof the entireset of variables. It is the dependent variable.set of variables. It is the dependent variable.
Potential Independent Variables Potential Independent Variables ::X1 = incomeX1 = income
X2 = education X2 = education
X3 = family sizeX3 = family size
X4 = ?? X4 = ??
The VariateThe Variate
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Types of Data and Measurement S cales Types of Data and Measurement S cales
DataData
Metric Metric or or
QuantitativeQuantitative
N onmetric N onmetric or or
QualitativeQualitative
N ominal N ominal S caleS cale
Ordinal Ordinal S caleS cale
Interval Interval S caleS cale
RatioRatioS caleS cale
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N onmetric N onmetric
oo N ominal N ominal size of number is not related to the amount of thesize of number is not related to the amount of thecharacteristic being measured characteristic being measured
oo Ordinal Ordinal larger numbers indicate more (or less) of thelarger numbers indicate more (or less) of thecharacteristic measured, but not how much more (or less).characteristic measured, but not how much more (or less).
Metric Metric
oo Interval Interval contains ordinal properties, and in addition, therecontains ordinal properties, and in addition, thereare equal differences between scale points.are equal differences between scale points.
ooR
atioR
atio contains interval scale properties, and in addition,contains interval scale properties, and in addition,there is a natural zero point.there is a natural zero point.
N OT E: The level of measurement is critical in determining theN OT E: The level of measurement is critical in determining theappropriate multivariate technique to use! appropriate multivariate technique to use!
Measurement S cales Measurement S cales
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All variables have some error. W hat are theAll variables have some error. W hat are the
sources of error? sources of error? Measurement error = distorts observed Measurement error = distorts observed
relationships and makes multivariaterelationships and makes multivariatetechniques less powerful.techniques less powerful.
Researchers use summated scales, for whichResearchers use summated scales, for which
several variables are summed or averaged several variables are summed or averaged together to form a composite representation together to form a composite representation of a concept.of a concept.
Measurement E rror Measurement E rror
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In addressing measurement error, researchers In addressing measurement error, researchers
evaluate two important characteristics of evaluate two important characteristics of measurement :measurement :
Validity = the degree to which a measureValidity = the degree to which a measureaccurately represents what it is supposed to.accurately represents what it is supposed to.
Reliability = the degree to which the observed Reliability = the degree to which the observed
variable measures the true value and is thus variable measures the true value and is thus error free.error free.
Measurement E rror Measurement E rror
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S tatistical S ignificance and Power S tatistical S ignificance and Power
Type I error Type I error , or , or EE, is the probability of rejecting the null , is the probability of rejecting the null hypothesis when it is true.hypothesis when it is true.
Type II error Type II error , or , or FF, is the probability of failing to reject the null , is the probability of failing to reject the null hypothesis when it is false.hypothesis when it is false.
Power Power , or , or 11- - FF, is the probability of rejecting the null hypothesis , is the probability of rejecting the null hypothesis when it is false.when it is false.
H H 0 0 t rue t rue H H 0 0 fals e fals e
F ail to Rejec t H F ail to Rejec t H 0 0 11--EE FF
Type II error Type II error
Rejec t H Rejec t H 0 0 EE
Type I error Type I error
11--FF
Power Power
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Power is Determined by Three Factors :Power is Determined by Three Factors :
E ffect size:E ffect size: the actual magnitude of the effect of the actual magnitude of the effect of interest (e.g., the difference between means or theinterest (e.g., the difference between means or the
correlation between variables).correlation between variables). Alpha ( Alpha ( EE):): as as EE is set at smaller levels, power is set at smaller levels, power
decreases. Typically,decreases. Typically, EE = .05.= .05.
S ample size:S ample size: as sample size increases, power as sample size increases, power increases. W ith very large sample sizes, even very increases. W ith very large sample sizes, even very
small effects can be statistically significant, raisingsmall effects can be statistically significant, raisingthe issue of practical significance vs. statistical the issue of practical significance vs. statistical significance.significance.
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Figure 1Figure 1--1 Impact of S ample S ize on Power 1 Impact of S ample S ize on Power
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Rules of Thumb 1Rules of Thumb 111
Statistical Power Analysis
� Researchers should always design the study to achieve
a power level of .80 at the desired significance level.� More stringent significance levels (e.g., .01 instead of
.05) require larger samples to achieve the desired
power level.
� Conversely, power can be increased by choosing a less
stringent alpha level (e.g., .10 instead of .05).� Smaller effect sizes always require larger sample sizes
to achieve the desired power.
� Any increase in power is most likely achieved by
increased sample size.
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Types of Multivariate Techniques Types of Multivariate Techniques
Dependence techniques :Dependence techniques : a variable or set of variables a variable or set of variables is identified as the dependent variable to be predicted is identified as the dependent variable to be predicted or ex plained by other variables known as independent or ex plained by other variables known as independent
variables.variables.
oo Multiple Regression Multiple Regression
oo Multiple Discriminant Analysis Multiple Discriminant Analysis
oo Logit/Logistic Regression Logit/Logistic Regression
oo Multivariate Analysis of Variance (MAN OV A) and Multivariate Analysis of Variance (MAN OV A) and CovarianceCovariance
oo Conjoint Analysis Conjoint Analysis
oo Canonical Correlation Canonical Correlation
oo S tructural E quations Modeling ( SE M)S tructural E quations Modeling ( SE M)
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Interdependence techniques :Interdependence techniques : involve theinvolve thesimultaneous analysis of all variables in the set,simultaneous analysis of all variables in the set,
without distinction between dependent variables without distinction between dependent variables and independent variables.and independent variables.
oo Principal Components and Common Factor Analysis Principal Components and Common Factor Analysis
oo Cluster Analysis Cluster Analysis
oo Multidimensional S
caling (perceptual mapping)Multidimensional S
caling (perceptual mapping)oo Correspondence Analysis Correspondence Analysis
Types of Multivariate Techniques Types of Multivariate Techniques
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S electing a Multivariate TechniqueS electing a Multivariate Technique
1.1. W hat type of relationship is being ex amined W hat type of relationship is being ex amined dependence or interdependence? dependence or interdependence?
2.2. Dependence relationship: How many variables areDependence relationship: How many variables arebeing predicted? being predicted? W hat is the measurement scale of the dependent W hat is the measurement scale of the dependent
variable? variable? W hat is the measurement scale of the predictor W hat is the measurement scale of the predictor
variable? variable? 3.3. Interdependence relationship: Are you ex aminingInterdependence relationship: Are you ex aminingrelationships between variables, respondents, or relationships between variables, respondents, or objects? objects?
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Multiple Regression Multiple Regression
Asingle metric dependent
Asingle metric dependent
variable is predicted by variable is predicted by
several metric independent several metric independent
variables.variables.
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A non A non--metric (categorical)metric (categorical)
dependent variable is predicted by dependent variable is predicted by
several metric independent variables.several metric independent variables.
Discriminant Analysis Discriminant Analysis
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Logistic Regression Logistic Regression
A single nonmetric dependent variable is A single nonmetric dependent variable is
predicted by several metric independent predicted by several metric independent
variables. This technique is similar tovariables. This technique is similar to
discriminant analysis, but relies on calculations discriminant analysis, but relies on calculations
more like regression.more like regression.
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MAN OV AMAN OV A
S everal metric dependent variables S everal metric dependent variables
are predicted by a set are predicted by a set of nonmetric of nonmetric
(categorical) independent variables.(categorical) independent variables.
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C AN O N IC AL ANALY S I S C AN O N IC AL ANALY S I S
S everal metric dependent variables S everal metric dependent variables are predicted by several metric are predicted by several metric independent variables.independent variables.
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. . . is used to understand . . . is used to understand respondents preferences for respondents preferences for products and services.products and services.
I n doing this, it determines theI n doing this, it determines the
importance of importance of bothboth::
attributesattributes and and
levels of attributeslevels of attributes
. . . based on a smaller subset of . . . based on a smaller subset of
combinations of attributes and combinations of attributes and
levels.levels.
CO N JOI N T ANALY S I S
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S tructural E quations Modeling ( SE M)S tructural E quations Modeling ( SE M)
E stimates multiple, interrelated dependence
E stimates multiple, interrelated dependencerelationships based on two components :relationships based on two components :
1.1. S tructural Model S tructural Model
2.2. Measurement Model Measurement Model
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. . . .. . . . analyzes the structure of theanalyzes the structure of theinterrelationships among a large number of interrelationships among a large number of variables to determine a set of common variables to determine a set of common
underlying dimensions (factors).underlying dimensions (factors).
Factor Analysis
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. . . .. . . . groups objects (respondents, products,groups objects (respondents, products,firms, variables, etc.) so that each object is firms, variables, etc.) so that each object is similar to the other objects in the cluster and similar to the other objects in the cluster and different from objects in all the other clusters.different from objects in all the other clusters.
Cluster Analysis Cluster Analysis
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Multidimensional S calingMultidimensional S caling
. . .. . . identifies unrecognized dimensions that identifies unrecognized dimensions that affect purchase behavior based on customer affect purchase behavior based on customer judgments of :judgments of :
similarities similarities or or
preferences preferences
and transforms these into distances and transforms these into distances represented as perceptual maps.represented as perceptual maps.
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Correspondence Analysis Correspondence Analysis
. . .. . . uses non uses non--metric data and evaluates metric data and evaluates
either linear or non either linear or non--linear relationships in an linear relationships in an
effort to develop a perceptual mapeffort to develop a perceptual map
representing the association between objects representing the association between objects
(firms, products, etc.) and a set of descriptive(firms, products, etc.) and a set of descriptive
characteristics of the objects.characteristics of the objects.
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G uidelines for Multivariate Analysis G uidelines for Multivariate Analysis
E stablish Practical S ignificance as W ell as E stablish Practical S ignificance as W ell as
S tatistical S ignificance.S tatistical S ignificance. S ample S ize Affects All Results.S ample S ize Affects All Results.
Know Your Data.Know Your Data.
S trive for Model Parsimony.S trive for Model Parsimony.
Look at Your E rrors.Look at Your E rrors.
Validate Your Results.Validate Your Results.
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S tage 1:S tage 1: Define the Research Problem, Objectives, and Define the Research Problem, Objectives, and
Multivariate Technique(s) to be U sed Multivariate Technique(s) to be U sed
S tage 2 :S tage 2 : Develop the Analysis Plan Develop the Analysis Plan S tage 3 :S tage 3 : E valuate the Assumptions U nderlying theE valuate the Assumptions U nderlying the
Multivariate Technique(s)Multivariate Technique(s)
S tage 4:S tage 4: E stimate the Multivariate Model and Assess E stimate the Multivariate Model and Assess
Overall Model Fit Overall Model Fit S tage 5 :S tage 5 : Interpret the Variate(s)Interpret the Variate(s)
S tage 6:S tage 6: Validate the Multivariate Model Validate the Multivariate Model
A S tructured Approach toA S tructured Approach toMultivariate Model Building:Multivariate Model Building:
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V ariable DescriptionV ariable Description V ariable TypeV ariable Type
Data Warehouse Classification VariablesData Warehouse Classification Variables
X1X1 Customer TypeCustomer Type nonmetric nonmetric X2 X2 I ndustry TypeI ndustry Type nonmetric nonmetric
X3X3 F irm SizeF irm Size nonmetric nonmetric
X4X4 R egionR egion nonmetric nonmetric
X5 X5 Distribution SystemDistribution System nonmetric nonmetric
Performance Perceptions VariablesPerformance Perceptions Variables
X6 X6 P roduct Quality P roduct Quality metric metric
X7 X7 E E- - Commerce Activities/WebsiteCommerce Activities/Website metric metric
X8 X8 Technical Support Technical Support metric metric X9X9 Complaint R esolutionComplaint R esolution metric metric
X10 X10 Advertising Advertising metric metric
X11X11 P roduct LineP roduct Line metric metric
X12 X12 Salesforce I mageSalesforce I mage metric metric
X13X13 Competitive P ricing Competitive P ricing metric metric
X14X14 Warranty & ClaimsWarranty & Claims metric metric
X15 X15 N ew P roductsN ew P roducts metric metric
X16 X16 O rdering & Billing O rdering & Billing metric metric X17 X17 P rice F lexibility P rice F lexibility metric metric
X18 X18 Delivery Speed Delivery Speed metric metric
Outcome/Relationship MeasuresOutcome/Relationship Measures
X19X19 SatisfactionSatisfaction metric metric
X20 X20 Likelihood of R ecommendationLikelihood of R ecommendation metric metric
X21X21 Likelihood of F uture P urchaseLikelihood of F uture P urchase metric metric
X22 X22 Current P urchase/Usage Level Current P urchase/Usage Level metric metric
X23X23 Consider Strategic Alliance/ P artnership in F utureConsider Strategic Alliance/ P artnership in F uture nonmetric nonmetric
Description of HB AT Primary Database Variables Description of HB AT Primary Database Variables
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Multivariate Analysis Multivariate Analysis Learning Checkpoint :Learning Checkpoint :
1.1. W hat is multivariate analysis? W hat is multivariate analysis?
2.2. W hy use multivariate analysis? W hy use multivariate analysis? 3.3. W hy is knowledge of measurement scales W hy is knowledge of measurement scales
important in using multivariate analysis? important in using multivariate analysis?
4.4. W hat basic issues need to be ex amined W hat basic issues need to be ex amined
when using multivariate analysis? when using multivariate analysis?
5.5. Describe the process for applyingDescribe the process for applying
multivariate analysis.multivariate analysis.