Data Scientists Interview Questions

54,242 data scientists interview questions shared by candidates

Given an array of sorted numbers ex: [1,1,1,2,2,2,2,2,2,2,3,3,3,3] find the indices where a single number starts and ends (ex: 1, start index=0, end_index=2). You have to solve this in log(n) complexity, you cannot go through every sample (n complexity).
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Research Scientist

Interviewed at Meta

3.6
Apr 18, 2019

Given an array of sorted numbers ex: [1,1,1,2,2,2,2,2,2,2,3,3,3,3] find the indices where a single number starts and ends (ex: 1, start index=0, end_index=2). You have to solve this in log(n) complexity, you cannot go through every sample (n complexity).

Two tables: User actions: date|sessio_id|userid|event session details: date|Sessionid|timespent_Sec|userid 1. Identify avg time spent per user per day 2. Create a histogram of duration on x axis, no of users on y axis which is populated by volume in each bucket Product questions: 1. Wants to add a new banner on FB Market place which suggests to sell something on facebook , should they do it, what should be done to evaluate it ? 2. Market place transactions happen through messages - these messages went down by 10% in a month, should they be worried ? How would you go about analyzing it?
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Data Scientist

Interviewed at Meta

3.6
Apr 15, 2019

Two tables: User actions: date|sessio_id|userid|event session details: date|Sessionid|timespent_Sec|userid 1. Identify avg time spent per user per day 2. Create a histogram of duration on x axis, no of users on y axis which is populated by volume in each bucket Product questions: 1. Wants to add a new banner on FB Market place which suggests to sell something on facebook , should they do it, what should be done to evaluate it ? 2. Market place transactions happen through messages - these messages went down by 10% in a month, should they be worried ? How would you go about analyzing it?

Q: Given a function with inputs --an array with N randomly sorted numbers, and an int K, return output in an array with the K largest numbers. Q: 1. How does GMM/HMM work 2. Name some dimensional reduction method; I said PCA and we talked a bit about how PCA works and what's the physical intuiation 3. How K-means work, what kind of distance metric would you choose, what if different features have different dynamic range 4. How GMM works (EM algorithm)
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Applied Scientist

Interviewed at Amazon

3.5
Mar 9, 2016

Q: Given a function with inputs --an array with N randomly sorted numbers, and an int K, return output in an array with the K largest numbers. Q: 1. How does GMM/HMM work 2. Name some dimensional reduction method; I said PCA and we talked a bit about how PCA works and what's the physical intuiation 3. How K-means work, what kind of distance metric would you choose, what if different features have different dynamic range 4. How GMM works (EM algorithm)

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