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Chapter 7 Multivariate techniques with text Parallel embedded system design lab 이청용

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Chapter 3(2.8)

Chapter 7Multivariate techniques with textParallel embedded system design lab7.1 IntroductionData collecting by taking measurements often unpredictableMeasurement errorRandomly selected objectsMultivariate statisticsTechniques for analyzing simultaneously text miningPrincipal components analysis 7.2 Basic statisticsSample variance

Z Scores Applied to PoeComputing how a data value compares to a data setConverting value dimensionless

7.2 Basic statistics

7.2 Basic statistics

7.2 Basic statistics

Z-score of 4for The Forest Reverie7.2.2 Word correlations among Poes short storiesZ-score has problem about comparing between units Correlation

7.2 Basic statistics

7.2 Basic statistics

7.2 Basic statistics

7.2 Basic statistics

7.2 Basic statistics

7.2 Basic statistics7.2.3 Correlations and cosines

Computing cosine using matrix multiplication7.2 Basic statistics7.2.3 Correlations and cosines

7.2 Basic statistics7.2.4 Correlations and covariancesCovariance

Correlation

7.3 Basic linear algebraSquare matrix X, M (having at least one nonzero vector)Satisfying

n by n correlation and covariance matrix n real, orthogonal eigenvectors with n real eigenvalues

= number7.3 Basic linear algebra7.3.1 2 by 2 correlation matrices

7.3.1 2 by 2 correlation matrices

7.3 Basic linear algebra

7.3.1 2 by 2 correlation matrices

7.3 Basic linear algebra

7.3.1 2 by 2 correlation matrices

7.3 Basic linear algebra

First : linear function of the originalSecond : vector C has unit lengthThird : each pair of and (i j)Four : the variances of , , , are ordered from largest to smallest7.4 Principal components analysis

7.4.1 Finding the principal componentsCorrelation matrixz-scoreCovariance matrixoriginal data values7.4 Principal components analysis7.4 Principal components analysis

Computing the principal components with function procmp()

7.4 Principal components analysis

Using summary() on the output of prcomp()

7.4 Principal components analysis

Computing the principal components using the covariance matrix7.4 Principal components analysis

Another PCA example with Poes short stories7.4 Principal components analysis

Another PCA example with Poes short stories

7.4 Principal components analysis

7.4 Principal components analysis7.4.4 RotationsOnly changing orientation but not the shape of any objectAny rotation in n-dimensions is representable by an n-by-n matrix

A PCA preserves all of the information