The Junior Data Scientist's First Month

100% practical 6-week data science challenge & video course -- simulating of being a junior data scientist at a true-to-life startup

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Start date: _________

You will receive a data science task every Monday, Wednesday and Friday for six weeks. After that, you will have unlimited access to this course and for all the tasks for as long as you like.

Price: _______ (In the EU, you have to pay additionally the VAT of your country as well.)

The max. number of attendees is 40!

ps. If you are from Hungary, please email me before you register: [email protected]

Get started now!

Hmmm... This is an older info page for this course. How did you get here? :-) Anyways, check out the current better, newer, longer, continously-updated version: HERE>>

Course Curriculum

The agenda of the 6 weeks

If you enroll, you will receive a data science task every Monday, Wednesday and Friday for six weeks. One or two days after receiving each task you will get the solution from me: the code base sent in text format and the detailed explanation sent in video format. The tasks:


Monday: I’ll send you the intro videos and you will also set up your own data server (with SQL, Python, pandas, numpy, etc.). I’ll give you free access to my other 1-hour video course and a 2-month coupon for a DigitalOcean data server.

Wednesday: Get the raw data! We will download and transform the raw data of the Send-a-Tree startup.

Friday: Automate the dataload.


Monday: Put everything into SQL. (You will also set up SQL Workbench.)

Wednesday: We will automate the whole SQL import process. And then we will run some exploratory data analyses.

Friday: Create and analyze segments. You will try to give some advice to the hypothetical marketing department based on the data, focusing on the different subsegments: who to target and why! (Basic SQL task)


Monday: A more complicated segmentation task where you also have to run revenue calculations. (Intermediate SQL task)

Wednesday: Let’s take a step back and think a little bit about the most important business metrics. What can help you the most to measure the success of Send-a-Tree? Create the SQL query to get it! (Advanced SQL task)

Friday: Visualize! Once you have created your business metrics, you will want to present them in a meaningful way, so the whole company understands them! (Google Data Studio)


Monday: Funnels! We will generate a basic funnel to measure the purchase process and generate a visual. (Advanced SQL task)

Wednesday: Warm-up task to create a cohort analysis in Python for a smaller data set. (Basic Python task)

Friday: Cohort analysis on our real data set. (Basic Python task)


Monday: Basic predictions with Python. (Intermediate Python task)

Wednesday: We will predict the number of expected registrations -- using two different regression models! (Intermediate Python task)

Friday: We will try to categorize the unknown values in our data table using a powerful statistical concept called classification. (Advanced Python task)


Monday: You will get a new data set from another fictional startup and a final task to test your freshly gained data science knowledge. You will have 4 days to solve this new task, and if you send me your solution, I'll personally evaluate it and give you feedback about it.

Friday: Deadline for the final test task.

WEEK #7:

Monday: Evaluation of the final test task. Wrap-up.

Get started now!

Hmmm... This is an older info page for this course. How did you get here? :-) Anyways, check out the current better, newer, longer, continously-updated version: HERE>>

You will get access to these things:

16 Exciting data science tasks

26 Video solutions (~5 hours in total) with in-depth explanations

16 Code-based solutions, immediately usable

Dedicated class Slack group and the power of networking with fellow students and alumni

1-on-1 call to discuss your career path

Email Support - if you get stuck

+1 free access to another video tutorial on how to install your data server so you have a data environment to practice

Send-A-Tree, the hypothetical startup you will work on

(a video from the intro section of the course)

Your Instructor

Tomi Mester
Tomi Mester

Tomi Mester is a data analyst and researcher. He worked for Prezi, iZettle and several smaller companies as an analyst/consultant. He’s the author of the Data36 blog where he writes posts and tutorials on a weekly basis about data science, AB-testing, online research and data coding. He’s an O’Reilly author and presenter on conferences like TEDxYouth, Barcelona E-commerce Summit or Data Conf.

Frequently Asked Questions

How long do I have access to the course?
How does lifetime access sound? After enrolling, you have unlimited access to this course for as long as you like.
What if I am unhappy with the course?
I would never want you to be unhappy! If you are unsatisfied with your purchase, contact me in the first 30 days and I will give you a full refund.
How big is the data set you will work with?
The dataset grows day by day during the course as the new user data flows in. By the end of the course, in total you will work with a data set of 2.5 million lines and around 12 million data points.
What languages will we use in the course?
We will mainly use SQL and Python. And we will also use a little bit of bash. In this course, we won't work with R.
What if I don't know Python, SQL and bash yet?
If you don't know SQL, Python or Bash - or none of them - don't worry, most of the course participants are in the same situation. The point of this whole course is to show you the missing pieces of your current data science knowledge - for some this is less, for others this is more - and make you learn those missing parts via practical exercises. Just so you know, I’ve even had participants who started the course without knowing any of these data languages and they successfully finished it… Of course, they had to work harder than other participants but I think it was definitely worth it for them.
How much time does a task take?
A task will usually take 1 to 3 hours of active work, depending on your current data science knowledge.

"A big shout-out to Tomi for coming up with this remarkable course. As the name suggests, this course indeed gives you a sneak peek of a junior data scientist's life. Each and every task is very relevant to the core. I strongly feel that this is a perfect learning platform (including the blog!!) for someone who wants to get into the field of data science and has a limited programming background. Yes, I was one of them and it did help me in getting the basics right and I hope it will help others too. Good luck to the future participants."

- Nisha, Singapore (Note: Nisha works as a Junior Data Scientist now.)

"I presented Send-A-Tree (the hypothetical startup project from the course) as a sample case study during my interview session for a Data Analyst job. I've got hired. Now, I am working there as a full-time DA."

- Balazs, Budapest, Hungary

"Following the promising reviews for JDS course, I registered and successfully completed the course. My aim was to refine my data analysis skills. It is a different course and this is where you will definitely make a remarkable change in your learning curve. But what makes it even better is the way the coach, Tomi ensures that everyone is on track, understanding the course material and enjoying it. In my case, I really enjoyed the course and did not feel it stressful even if there was a lot of new material. I would therefore, highly recommend it if you are seeking to start or improve your analytics skills. Big thanks, Tomi!"

- Asmeeta, London, United Kingdom (Note: Asmeeta currently works as Management Information Analyst.)

"This course provided me with a lot of insights about the necessary coding skills as well as the business thinking which every Data Scientist should have!"

- Tomi Gelo, Berlin, Germany

"The BEST online training course for Data Science on the market, in my opinion! I learned more from Tomi's JDS course than I've learned from the two previous online courses I enrolled in---COMBINED! "

- Greg, Pennsylvania, USA

"I've been following Data36, and I knew that Tomi was a great Data Scientist but I never thought that he was this good at teaching. When I saw the syllabus I was afraid that six weeks would be too short for it. Bash, SQL, and Python in just six weeks? Then the course started, Tomi supplied the materials in chunks to not overwhelm his students and thank god for that. The course was easy to follow, with real-world exercises/problems and a dedicated teacher that was available via Slack, Email and Call. If you ask me, it can't get better than that."

- Nuno S., Cape Verde

"This course is very well designed and well paced. The videos and tasks took just the right amount of time to be completed, exactly what I needed to stay engaged to be able to finish the course on time. During the course, it felt like Tomi was mentoring me, showing his workflow, inspiring me and also challenging me to think critically. This course definitely gave me confidence and direction to keep developing myself in this area."

- Marcus, Stockholm, Sweden

"I found Data36 while thinking about what to do with my career on a sandy beach in Bali. After going through a number of Tomi's SQL tutorials and webinars I decided to go a step further and take the course.

The course sets you up with everything you need to get going. More importantly, it was clear that Tomi was going to be a friendly and relaxed mentor. The course content set you up with a technical foundation but also the mindset that gives you the capacity to approach the tasks successfully.

The course was more than manageable with a full-time job. When I did feel slightly against it, Tomi was more than happy to extend the deadline for personal feedback. I felt like I had achieved a lot after 6 weeks, so a big thank you to Tomi!"

- Stephen, United Kingdom

"The Junior Data Scientist course provides a very practical, approachable, and enjoyable tour of the actual processes and tools required to turn raw data into actionable insights. I highly recommend it and Tomi who was responsive and helpful throughout the course."

- Robert, California, USA

Get started now!

Hmmm... This is an older info page for this course. How did you get here? :-) Anyways, check out the current better, newer, longer, continously-updated version: HERE>>