Ace the Data Interview
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CMU Data Science Club
By Nick Singh
About Nick Singh
At UVA:
Studied Systems Engineering & Computer Science
Data Science Intern @ Office of Naval Intelligence
Data Engineering Intern @ Google
Early Career:
Growth Engineer at Facebook
Multiple Hats @ Location Analytics Startup SafeGraph
For Fun:
DJ Lil’ Singh & Drake’s #1 Fan
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Agenda
By the end of this talk you’ll learn…
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Behavioral Interviews &
Portfolio Projects
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But there was one slight problem…..
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Users signed up… then churned out :(
Why did they churn out?
How can get users to return to the game?
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The Solution:
Growth Engineering!
(a combo of Product Analytics, A/B Testing, and Software Engineering)
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2,000 Monthly Active Users Later…
I Had Fallen In Love
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Behavioral Interview Questions:
Why Facebook?
Why Growth Engineering at Facebook?
Behavioral Interview Questions:
Tell Me About a Time where you…
Analyzed data to find an insight
Ran an A/B test
Built something for consumers
Learned something new
Ran into a technical challenge
Did data analysis which impacted the product roadmap
Biden Dad Joke Maker
Your project doesn’t have to be fancy!
SQL + Tableau can go a long way!
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Are Technical Interviews Easy or Hard?
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Has anyone done a technical interview before?
How many technical interviews have you done before?
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Technical Topics Interviews Often Cover
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Core Concepts for Prob & Stat Questions
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Common Patterns for Prob, Stat, & ML Questions
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“Explain Like I’m Five” Tips
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Common Patterns for Prob, Stat, & ML Questions
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Common Patterns for Prob, Stat, & ML Questions
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Examples of ‘Obvious’ Prob & Stat Questions:
Say you have a sample size of N. The margin of error for the sample size is 3. How many more samples do you need to decrease the margin of error to 0.3?
Say you have a deck of 50 cards made up of cards in 5 different colors, with 10 cards of each color, numbered 1 through 10. What is the probability that two cards you pick at random do not have the same color and are also not the same number?
A coin was flipped 1,000 times, and 550 times it showed heads. Do you think the coin is biased? Why or why not?
550 heads out of 1,000 coin tosses.
Do you think the coin is biased?
Why or why not?
550 heads out of 1000 coin tosses. Is the coin biased?
ⓘ Start presenting to display the poll results on this slide.
A coin was flipped 1,000 times, and 550 times it showed heads. Do you think the coin is biased? Why or why not?
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Common Patterns for Prob, Stat, & ML Questions
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Survey Design:
We want to conduct a survey to see how people perceive our Disney+ UI versus the Netflix UI (is it easy to use, is it beautiful, which one do they prefer, etc.)?
Survey Design:
We want to conduct a survey to see how people perceive our Disney+ UI versus the Netflix UI (is it easy to use, is it beautiful, which one do they prefer, etc.)?
How many people should we survey?
How many people should we survey?
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Survey Design:
We want to conduct a survey to see how people perceive our Disney+ UI versus the Netflix UI (is it easy to use, is it beautiful, which one do they prefer, etc.)?
Why can’t we just survey a TON of people?
Survey Design:
How many people should we survey?
How well do you know SQL?
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https://datalemur.com/questions/sql-histogram-tweets
https://datalemur.com/questions/sql-histogram-tweets
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The poll was deleted
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Open-Ended
Analytics Case Interviews
Open Ended Case Study
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Open Ended Case Study: Applied to Facebook Dating
What metrics would you use to define the success of Facebook Dating?
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What metrics would you use to define the success of Facebook Dating?
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Uber Interview Question
What metrics would you track to make sure Uber’s surge pricing algorithm was working well?
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How would you build Uber’s surge pricing algorithm?
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“ETAs spiked to 8 minutes and the share of trip requests unfulfilled rose to 25 percent”
Are Technical Interviews Easy or Hard?
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Technical Interviews Are Hard
Technical Interviews Are Easy
Technical Interviews Are Easy
Technical Interviews
Are Hard
But with practice it becomes
Easier
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Audience Q&A
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