By Thom Marra Marra & Associates, LLC. The Big Picture Know your story line, the Y’s and the X’s...
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Transcript of By Thom Marra Marra & Associates, LLC. The Big Picture Know your story line, the Y’s and the X’s...
Marra & Associates, LLC
Graphical Analysis of DataBy Thom Marra
Marra & Associates, LLC
The Big PictureKnow your story line, the Y’s and the X’sThink through what statistics you are likely to
useCollect the dataHow much data do you have?Is it stable?See the data (graphs and tables)Analyze using descriptive and inferential
statistics
Marra & Associates, LLC
Know the Story LineDetermine what is your primary metric(s)
The Y in Y = f(x)What is the business reason for collecting the
data?Do an initial thought process on relationships
to Y (what are the X’s in Y = f(x))
Marra & Associates, LLC
Data Collection – types of dataContinuousDiscrete
BinaryOrdinalNominal
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Data VisualizationLook for outliersFix spelling and grouping errorsGraphs for continuous dataGraphs / tables for discrete dataAnnotating graphs
Marra & Associates, LLC
Data Visualization - outliersTime series plotOpen Newmarket.mtwGraph/time series plot
Marra & Associates, LLC
Data Visualization - spellingSpelling errors cause improper subgroupsOpen Exh_tabl.mtwStat/tables/tally individual values
Marra & Associates, LLC
Data Visualization – continuous dataA list from the graph’s menu
Use stat/regression/fitted line plot
Use stat/basic stats/graphical summary
Marra & Associates, LLC
Data Visualization – scatterplotUse scatterplots when Y and X are continuousUse stat/regression/fitted line plotOpen Exh-regr.mtw
Marra & Associates, LLC
Data Visualization - histogramsUse histograms to visually see the shape of the dataUse stat/basic statistics/graphical summaryOpen Pulse.mtw
Marra & Associates, LLC
Data Visualization – boxplotsUse boxplots when you have more than 30
data points per subgroupOpen Pulse.mtwGraph/boxplots
Marra & Associates, LLC
Data Visualization – individual value plot
Use individual value plots when you have small amount of data for each subgroup
Open Pulse.mtwGraph/individual value plot
Marra & Associates, LLC
Data Visualization – individual value plot
Marra & Associates, LLC
Data Visualization - tablesTables are the best way to display exact
numerical values for small data sets
Group Before After
A 53 60
B 46 40
C 57 55
This table is easier to compare values than the Pie chart.
Marra & Associates, LLC
Marra & Associates, LLC
Data Visualization – Pareto ChartsOpen Exh_qc.mtwStat/Quality Tools/Pareto
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Data Visualization - annotationMake sure all worksheet are named properlyTools/Options/Graphics/Annotation/My
Footnotes
Marra & Associates, LLC
Data Visualization - annotationMake sure all column names are clear,
spelled correctly and carry the proper capitalization.
From the Tool bar select “T” and add text to clarify graphs.
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Marra & Associates, LLC
Data Analysis – population attributes
Location
S p r e a d
S H A P E
CONSISTeNCy
Marra & Associates, LLC
Data Analysis – descriptive statisticsOpen Furnace.mtwStat/Basic Statistics/Graphical Summary
Marra & Associates, LLC
Data Analysis – conclusionsFollow the roadmap for additional hypothesis testsUse GLM or Multiple Regression for more than one XMake a list of the “Vital Few X’s.” Also make a list of
those X’s that were the “Trivial Many.”Draw conclusions based on all of your knowledge
(scientific principles, wisdom of the wise, graphical and statistical output)
Make practical decision. Remember you cannot have a practical difference if there is not a statistical difference.
Solve the current opportunity and move on to the next opportunity
Have fun!
Marra & Associates, LLC