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Tips, tricks and ideas for analysing
real-life data sets in Minitab
Quentin Brook
Minitab Insights, Philadelphia 2016
Process improvement
consultant and author.
Live in Winchester, UK.
Married, father of two.
Fishing, running and pubs.
linkedin.com/in/quentinbrook
Quentin Brook
Checking and preparing data
Understand where it came from.
Check it represents what you think it does.
Get a feel for its quality.
Prepare it for further analysis.
Checking and preparing data
Let’s take a look at some real data…
Take your time – it’s an investment.
Don’t assume anything!
Checking and preparing data
First Pass Analysis
To gain a rapid, high level understanding of
historical process performance.
To get to know the data and look for clues
for further analysis.
First Pass Analysis
Let’s take a look at our real data…
Sample ‘window’
Time
Collection ‘moment’
Lead time data collection issues
1404124810929367806244683121561
200
150
100
50
0
Index
Tim
e t
o r
eso
lve
Time Series Plot of Time to resolve
Lead time data collection issues
Lead time data collection issues
15101359120810579067556044533021511
200
150
100
50
0
Index
Tim
e t
o r
eso
lve
of Time to Resolve ordered by Open Date but with data cut off at end of sample peri
Lead time data collection issues
1404124810929367806244683121561
200
150
100
50
0
Index
Tim
e t
o r
eso
lve
Time Series Plot of Time to resolve ordered by Resolve date
Be inquisitive – look for strange things, but
don’t read too much into the minutiae.
Have a play with the data – there are no
rights or wrongs.
First Pass Analysis
What to do with too much data.
What to do with too much data.
XBar-R Charts
Sampling
Let’s take a look at our real data…
What about Normality?
What about Normality?
Non-Normal data ≠ bad data!
Investigative analysis
Investigative analysis
Don’t just jump right in!
What’s your theory > What graph is right for the job?
It’s at this point that there’s a gulf between basic
spreadsheet software (e.g Excel) and specialist
software (e.g Minitab).
Some analysis examples from our real data…
Keeping track of your analysis.
‘Storyboarding’ is the key!
Be diligent – summarise as you go in the ReportPad.
Keeping track of your analysis
Using ReportPad with our data…
In summary
Take the time to get to know your data.
Be inquisitive and ‘listen to your data’.
Don’t worry too much about Normality.
Let your theories and ideas drive your analysis,
then choose the right graph.
Storyboard as you go, or regret it later!
Thank you.