hmwangi / interview-questions

Data Science Interview Question and Preparation Documentation

Data Science Interviews

Data science interview questions - with answers

The answers are given and create from various industry professional

• If you know how to answer a question — please create an issue with the answer
• If there's already an answer, but you can improve it — please create a Pull Request with improvement suggestion
• If you see a mistake — please create a Pull Request with a fix
• If you would like to contribute - please create a Pull Request

Questions by category

• Theoretical questions: (linear models, trees, neural networks and others)
• Technical questions: (SQL, Python, coding)
• Data Science Glossary
• General Questions

CV Templates

There is folder containing some basic templates. Note that this is usually the documents that makes the first impression. There are other online sites that offer cv templates just make sure you can download it before you write up the whole CV.

Lessons Learned

I’m going to present a bunch of lessons I learned as bullet points in no particular order. Everything listed below is something I wish I knew beforehand, both in terms of preparation on the technical side and in terms of scheduling and other non-technical tips. These lessons are not industry specific and I’d imagine are generally applicable to all interviews in our current space.

📚 Stick with it.

It take times. I didn't land the first job I applied for or the second. However you have to continuely try and try again. Eventually, things started falling into place. It’s a lot of work, but the willingness to learn is what separates successful candidates from the rest.

🤓 Practice is almost everything.

You certainly need a baseline of innate ability, but practice (i.e. learning) can fill in very wide ability gaps. Companies don’t hire people based on the knowledge they were born with. They hire those that can perform their duties and perform them well, regardless of where/when they cultivated the knowledge.

👫 Practicing with a friend is everything else.

Whether on a whiteboard or on something like Codeshare, simulating an interview environment with someone over a period of time takes a lot of the scariness out of interviews. You get over the awkwardness of verbalizing something totally stupid to someone because your brain slipped. The best is if you can make sure someone understands a problem you haven’t seen before, as they can give you hints to push you toward a solution. Seriously, that kind of practice is invaluable.

📊 It’s a numbers game.

You can practice — effectively, even — and not land a job because the right person didn’t see your resumé or you just didn’t see a solution to a whiteboard problem in time. The best you can hope to do is maximize your odds. This means applying everywhere you would like to work and fit a job req and not just your top choice. I applied for my top 20!

🤔 Focus on the problem solving, not the solution.

Memorization isn’t enough. Of ~20 algorithm problems I saw in a week I had seen maybe one of the problems before (and I let my interviewer know, though many would disagree with that choice). I just saw lots of common patterns and I was able to come up with solutions on the fly.

😣 Don’t get discouraged.

There were multiple interviews I had where I didn’t know the solution and interviewers had to shepherd me towards a solution. I still got offers from everywhere I interviewed. Also, I felt I absolutely bombed one of my interviews (four of my five that day I thought were solid “no hires”) and the company later extended me an offer. Anything can happen, evidently. :)

🤯 Don’t be quick to disregard problems.

There were multiple times I was practicing with a friend of mine and he shrugged off particularly difficult problems as pointless to know. Curiously enough, of the four types of problems I recall him saying would “never” come up, two of them did. Not in the exact form we were going to practice, but very similar. If your practice shows a certain concept come up frequently, learn it.

🧐 Don’t underestimate the importance of behavioral questions.

I think I enjoyed a lot of success because my (honest) answers were what companies wanted. It’s my theory that many developers have strong technical skills and still struggle to find their perfect job because they’re rude, dishonest, or uncomfortable speaking to people outside of a technical setting. These are all justifiable reasons to reject a candidate, in my opinion. Practice them just as you would technical questions.

🧠 If you know more, show it.

There were multiple examples during my onsites where I would answer a question and mention some other knowledge I had but explain that I didn’t have time in an interview to fully implement that solution. Answering a question about strings? Show off your Unicode knowledge with your solution or explain how to support Unicode. Implementing a private method? Talk about the Objective-C conventions for methods. Updating a table view? Talk about the different animations you can support. Don’t bring something up if you can’t talk all about it, but if you can, it allows you to show knowledge outside of the narrow window provided by the question and gives you a leg up on anyone that sticks strictly to the beaten path.

💪 Don’t strive to clear the bar, strive to set it.

Interview performance obviously helps decide if you get an offer from a given company, but it also helps decide what that offer looks like. If you get to a point where you think you know enough to get an offer, that’s great. But keep in mind there’s a big difference between “barely good enough” and “absolutely good enough”. Strive for the latter! My initial (i.e. not negotiated) offers came in pretty solid despite my relative lack of experience and I believe interview performance played a big role.

Sites you used know

Sites to get an Internship

1. LinkedIn
2. Indeed
3. Internships
4. Glassdoor
5. Idealist
6. Absolute Internship
7. LookSharp
8. Intern Queen
9. Internship Programs
10. Alma Mater

Top 10 Sites for your Job Search

1. Indeed
2. LinkedIn
3. Dice
4. Glassdoor
5. Idealist
6. Career Builder
7. LinkUp
8. Google for Jobs
9. Monster
10. US Jobs

Sites to Build your Resume

1. Canva
2. KickResume
3. Visual CV
4. Zety
5. Free Resume Templates
6. NovoResume
7. MyPerfectResume
8. Resume Genius
9. Pongo
10. Creddle

Top Sites to Learn Tech Skills

1. Treehouse
2. Khan Academy
3. Code School
4. EDX
5. CourseEra
6. CodeWars
7. FreeCodeCamp
8. GitHub
9. The Odin Project
10. MIT OpenCourseWare

Sites for Free Online Education

1. Udacity
2. Code Avengers
3. David Walsh Blog
4. Tuts+
5. SitePoint
6. HTML5 Rocks
7. Hack.Pledge()
8. Agupieware
9. Crunchzilla
10. Dash General Assembly
11. CodeAcademy
12. Infinite Skills
13. Lynda
14. CodeHS
15. Udemy

Sites to practice Coding

1. HackerRank
2. Codewars
3. Kaggle
4. Zindy
5. W3schools