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Statistics for hackers @sbelak [email protected]

Statisics for hackers

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A 80/20 approach to getting maximal insight in the shortest time and for the least fuss from your data (and a tour of corresponding pitfalls).

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Statistics for hackers@sbelak!

[email protected]

Data science = storytelling

What to measure?

Metrics to Help You Make Wise Decisions About Your Start-Up

• Customer Acquisition Cost (CAC) • Activation • Retention - Churn (attrition) • Life Time Value (LTV) • Conversions • Revenue MRR • Referral

Good metrics Are Actionable ] optimize

Can be Audted

Are Accessible ]! understand!

An actionable metric is one that ties!specific and repeatable actions !

to observed results.!—Ash Maurya!

Metrics are data for humans

Metrics have to hurt (and be actionable)

Why should we measure?!

Understand &

optimize

Capture time dynamics

Capture every event (not just touch points)

Usage cohort

User cohort

Time cohort

weeks

% a

ctiv

e us

ers

cohorts

Target customer

Typical customer→

dynamic

Target Typical

market analytics product analytics

Metrics vs. KPIs

Composite ↳ ratios ↳ comparable

!

!

Linked to product & story ↳ explainable ↳ indirect

What you actually measure

Focus on one KPI at a time

The ambulance response time problem

clustering

segmentation

clustering

segmentation

Statistics 101

32

33

Anscombe's quartet!

!

• same mean!• same variance!• same correlation!• same linear regression line!

2

1

3

<3 Visualizations

Bar chart/histogram Scatter plot/ line plot

Working with series

1st derivate: change!2nd derivate: change of change

The dead salmon conundrum

Correlation!!C

ausa

ti n!

cause!

symptom!

symptom!

symptom!

cause!

Your

metrics capture external relations!

Your

metrics capture external relations!

NORMAL

IZE!!

Sample size

• Significance!

• http://www.surveysystem.com/sscalc.htm!

• http://getdatadriven.com/ab-significance-test!

• 10 x 100 > 1000

More data > better model

Hustling data: proxy touch points

:)

:(

t

happ

ines

s

bounce

bounce

Sort!Normalize!Compose !Decompose (segment) !"

Algebra of data

Your tools shape your thoughts

Aggregate data in one place

Denormalize!co-occurrence begets serendipity !

(De)compose data

+

=

+

=

Data science = storytelling

Takeouts• More data > better model.

• You can get away with very little statistics if you are diligent with your visualizations.

• Metrics have to hurt (and be actionable).

• Time dynamics greatly enrich your data's explanatory power.

• Beware: humans are pattern matching machines and sometimes we see patterns where there are none.

• Beware: your metrics capture external relations.