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What does a data scientist do?
Alex Gilgur. Data Science & Predictive SPC
The Maslow Pyramid
Alex Gilgur. Data Science & Predictive SPC
The Maslow Pyramid of Data Science
IT Infrastructure
Software Engineering
Quantitative Analytics
Domain
Data
Alex Gilgur. Data Science & Predictive SPC
Data Science = Nuclear Energy
Blow up in our face
Alex Gilgur. Data Science & Predictive SPC
Data Science = Nuclear Energy
Blow up in our face
…or…
Alex Gilgur. Data Science & Predictive SPC
Data Science = Nuclear Energy
Blow up in our face
…or…
Give us Power
Alex Gilgur. Data Science & Predictive SPC
What’s the Team We’re Rooting For?
DATA
INFORMATION
8Alex Gilgur. Data Science & Predictive SPC
What’s the Team We’re Rooting For?
DATA
INFORMATION
9
INFORMATION
INFORMATION
Alex Gilgur. Data Science & Predictive SPC
What’s the Team We’re Rooting For?INFORMATION
10
INFORMATION
INFORMATION
Alex Gilgur. Data Science & Predictive SPC
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Servers = argmax (Revenue |Budget)
Revenue = f[Throughput (Servers, SW, Budget)]
Servers = argmin (Budget | Revenue)
•Throughput = t (UX)
•Revenue = r (Throughput)
•Budget = f(SW, Servers)
Constraints:•Domain•Budget ≤ B
From X to Y to X
Closing the Loop
∆ →
Arithmetic means of random samples taken from any distribution asymptotically converges to a normal distribution as the number of such samples tends to infinity.
CENTRAL LIMIT THEOREM
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σσ
σ
σ
σσ
σσ
σ
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Key
Per
form
ance
Met
ric (K
PM
)
72 hrs
LSL
USL
How did HAL Know?
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A Few Words About ForecastingMethods:
● EWMA● ARIMA ● Regression
EWMA models are very specific and computationally fast, but they have to be told trend (linear or exponential) and seasonality (additive or multiplicative).
ARIMA model will implicitly account for trends, seasonality, and stationarity of the data. Autocorrelation of ARIMA residuals provide all the periodicities that have been missed.
For stationary data, use ARIMAFor non-stationary data, use EWMAEWMA and ARIMA overlap
When to use Regression:● data are monotonic.● seasonality is NOT statistically significant.● EWMA and ARIMA fail.
When to use Quantile Regression:● Upper and Lower bounds behave differently.● Outliers are possible.
For each data set, we can run a model competition, computing forecast model quality based on a weighted sum of model goodness of fit, model suitability for forecasting, data stationarity and data variability, and selecting the model that works best for each data set.
EWMA
ARIMA
Quantile Regression
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p50R …
p50 R …
Target
(LCL…UCL)
(LSL…USL)
p50R …
p50 R …
Target
(LCL…UCL)
(LSL…USL)
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o
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••••
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www.isixsigma.com
www.amstat.org
www.cmg.org
www.linkedin.com
http://alexonsimanddata.blogspot.com/
http://josepferrandiz.blogspot.com/
“Statistical thinking will one day be as necessary for efficient citizenship as the ability to read and write.”
- H.G.Wells (1866-1946)
THANK YOU
•
http://en.wikipedia.org/wiki/Western_Electric_rules
http://en.wikipedia.org/wiki/Nelson_rules
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σσ
Universal Scalability Law
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