business research methods chap016
TRANSCRIPT
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16-2McGraw-Hill/Irwin © 2003 The McGraw-Hill Companies, Inc.,All Rights
Reserved.
Part FourANALYSIS AND
PRESENTATION OF DATA
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Chapter SixteenEXPLORING, DISPLAYING,
AND EXAMINING DATA
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Types of Data Analysis
• Exploratory data analysis– the data guide the choice of analysis--or a
revision of the planned analysis
• Confirmatory data analysis– closer to classical statistical inference in its
use of significance and confidence– may use information from a closely related
data set or by validating findings through the gathering and analyzing of new data
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Techniques to Display and Examine Distributions
• Frequency Table
• Visual Displays– Histograms
– Stem-and-leaf display
– Box-plot
• Crosstabulation of Variables
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Techniques to Display and Examine Distributions
• Histograms– Display all intervals in a distribution, even
without observed values– Examine the shape of the distribution for
skewness, kurtosis, and the modal pattern
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Techniques to Display and Examine Distributions (cont.)
• Box-plot (box and whisker-plot)– Rectangular plot encompasses 50% of
the data values• Edges of the box (hinges)
– Center line through the width of the box marks the median
– Whiskers extend from the right and left hinges to the largest and smallest values
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Techniques to Display and Examine Distributions (cont.)
• Transformation– To improve interpretation and
compatibility with other data sets
– To enhance symmetry and stabilize spread
– To improve linear relationships between and among variables
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Improvement & Control Analysis
• Statistical process control– Uses statistical tools to analyze, monitor,
and improve process performance– Total Quality Management– Control chart
• Displays sequential measurements of a process together with a center line and control limits
– Upper control limit
– Lower control limit
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Types of Control Charts
• Variables data
(ratio or interval measurements)– X-bar– R-charts– s-charts– Pareto Diagrams
• Bar chart whose percentages sum to 100 percent
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Geographic Information Systems
• Systems of hardware, software, and procedures that capture, store, manipulate, integrate, and display spatially-referenced data
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Geographic Information Systems
• Minimum four components– Integrating information from various
sources– Capturing data– Projection and restructuring– Modeling
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Crosstabulation
• A technique for comparing two classification variables– Cells– Marginals– Contingency tables
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Percentaging Errors
• Averaging percentages without weighting
• Using too-large percentages (>100%)
• Using percentage with very small sample
• Citing percentage decrease exceeding 100 percent
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Other Table-based Analysis
• Automatic Interaction Detection (AID)– Sequential partitioning procedure that uses a
dependent variable and set of predictors– Searches among up to 300 variables for the
best single division of data into subsets according to each predictor variable,
– Chooses one division approach – Splits the sample using chi-square tests to
create multi-way splits.