5 TikTok Data Science Interview Questions & Interview Prep Guide

Updated on 
February 8, 2024
by Nick Singh
By Nick Singh
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If you've got an upcoming Data Scientist interview at TikTok, look no further – in this article we'll cover 5 real TikTok Data Science interview questions, what these interviews generally cover, and tips and a guide on how to study for Data Science interviews at TikTok (and other FAANG companies more broadley.)

Before we jump into real TikTok interview questions, I want to introduce myself so this isn't just some random article by a random person you stumbled upon while frantically preparing for your TikTok interview. My name is Nick Singh, and I'm the author of the best-selling book Ace the Data Science Interview and founder of DataLemur (a free website to practice SQL interview questions). I've worked at Facebook and Google, so I absolutely understand how gruelling the technical interview process for data roles can be (and yes, TikTok DS interviews are difficult AF).

5 TikTok Data Science Interview Questions

Here's 5 real TikTok Data Science Interview questions that were asked recently in interviews. Because interviewers like to change things up, you won't necessarily be asked the same exact questions in your Data Science or Data Analyst interview, but hopefully this list of questions will be a great start to your interview prep.

Interview Question #1: Write a query to display the ids of TikTok users who confirmed on the second day.

This TikTok SQL interview question asks you to write a query to display the ids of the users who did not confirm on the first day of sign-up, but confirmed on the second day.

Hint: We definitely need an INNER JOIN to get the users who have activated their accounts by text-confirmation. To solve this SQL interview question yourself, try it out on DataLemur!

Interview Question #2: Explain the Bias-Variance Tradeoff.

Here, the interviewer is asking you to explain the classic bias-variance tradeoff that Data Scientists and Machine Learning engineers face when building models. You might be asked to give a concrete example, and also connect this tradeoff to the concept of overfitting.

Interview Question #3: Write a SQL query to find the activation rate of TikTok users.

New TikTok users sign up with their emails. They confirmed their signup by replying to the text confirmation to activate their accounts. Users may receive multiple text messages for account confirmation until they have confirmed their new account.

Write a query to find the activation rate of the users. Round the percentage to 2 decimal places.

The following steps are suggested to solve this question:

  1. Join tables and keep rows where there is successful confirmation.
  2. Use the CASE statement to assign values to users who have activated vs. those who have not.
  3. Calculate the signup activation rate.

To solve this TikTok SQL question, visit DataLemur (and get multiple hints + full solutions too!).

Interview Question #4: Tell us about a successful A/B test you designed in the past.

This question is trying to dive into your past Data Science experience, and gauge your Product Data Science skills. Don't let the simplicity of the question fool you – it's just the starting point for a deeper conversation. Follow on questions you'll likely get asked include:

  • How did you know to run an A/B test for this product/feature?
  • What was the business impact from the A/B test?
  • Did you run into any issues with user-imbalance?

If your applying for a Product Data Science role at TikTok, knowing the fundamentals of A/B testing are crucial!

Interview Question #5: What's the difference between correlation and co-variance?

Covariance shows you how the two variables differ, whereas correlation shows you how the two variables are related. A common follow-up question to expect is "How does changing the scale of variables affect correlation and covariance?". If you said it affects covariance, but has no effect on correlation, well done!

How To Prepare for TikTok Data Scientist Interviews

For more practice to ace the TikTok Data Scientist interview, check out this list of 40 Probability & Statistics interview questions – you'll see multiple experimentation interview questions from Product Data Science interviews at Airbnb, Facebook, and Uber.

You should also read Ace the Data Science Interview. Of course, I'm biased when I recommend my own book, but just read any of the 690+ 5-reviews on Amazon from Data Scientists who used this book to land their dream job at companies like Facebook, Coinbase, Airbnb and of course TikTok.

To preview the content from the book for free, practice some of the same Data Science Interview Questions on DataLemur or check-out the free 9-day Data Interview crash course. You can also find many of the SQL interview tips in the Ultimate SQL Interview Guide which should help you on the TikTok SQL screening assessments.

How to Prepare for the Data Science Interview at FAANG?

Getting a data science job at a FAANG company—Facebook, Amazon, Apple, Netflix, or Google—can be a game-changer for your career. These companies have tough interview processes to find the best talent. To succeed, you'll need to master key data science concepts, tackle real-world problems, and communicate your ideas clearly. In this section, we'll share practical tips and resources to help you get ready for your FAANG data science interview with confidence.

Here are two guides to help you conquer the interviews:

More Data Science Interview Books

For more resources to study for Data Science Interviews, check out a few other Data Science Interview prep books we recommend!

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