by thom marra marra & associates, llc. the big picture know your story line, the y’s and the...

Marra & Associates, LLC

Graphical Analysis of DataBy Thom Marra


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


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))


Data Collection – types of dataContinuousDiscrete

BinaryOrdinalNominal


Data VisualizationLook for outliersFix spelling and grouping errorsGraphs for continuous dataGraphs / tables for discrete dataAnnotating graphs


Data Visualization - outliersTime series plotOpen Newmarket.mtwGraph/time series plot


Data Visualization - spellingSpelling errors cause improper subgroupsOpen Exh_tabl.mtwStat/tables/tally individual values


Data Visualization – continuous dataA list from the graph’s menu

Use stat/regression/fitted line plot

Use stat/basic stats/graphical summary


Data Visualization – scatterplotUse scatterplots when Y and X are continuousUse stat/regression/fitted line plotOpen Exh-regr.mtw


Data Visualization - histogramsUse histograms to visually see the shape of the dataUse stat/basic statistics/graphical summaryOpen Pulse.mtw


Data Visualization – boxplotsUse boxplots when you have more than 30

data points per subgroupOpen Pulse.mtwGraph/boxplots


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


Data Visualization – individual value plot


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.


Data Visualization – Pareto ChartsOpen Exh_qc.mtwStat/Quality Tools/Pareto


Data Visualization - annotationMake sure all worksheet are named properlyTools/Options/Graphics/Annotation/My

Footnotes


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.


Data Analysis – population attributes

Location

S p r e a d

S H A P E

CONSISTeNCy


Data Analysis – descriptive statisticsOpen Furnace.mtwStat/Basic Statistics/Graphical Summary


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!

by thom marra marra & associates, llc. the big picture know your story line, the y’s and the...

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