Hey, I'm Tomi Mester. This is my data blog, where I give you a sneak peek into online data analysts' best practices. You will find here articles and videos about data analysis, AB-testing, researches, data science and more...
I decided to create a dictionary which unifies the most used data expressions and places them within a clear framework. This is an 54 pages handbook and actually it’s…
Read these 7 free articles about Bash/Command Line and take your very first step to learn the basics of coding for Data Science!
If you are learning Data Science, pretty soon you will meet Python. Why is that? Because that’s one of the most commonly used data languages. The popularity of…
In the last 2 weeks I’ve introduced 9 common statistical bias types. If you went through them, you have already done the first very important step to overcome…
It’s time to continue our discourse about Statistical Bias Types. This is part 2 – if you missed part 1, read it here: Statistical Bias Types part 1….
Humans are stupid. We all are, because our brain has been made that way. The most obvious evidence to this built-in stupidity is the different biases, that our…
The usefulness of visualisations in data analysis is often questioned. At the end of the day, the outcome of the analysis should be quantifiable, right? Well, maybe. But…
This is the final episode of the SQL for Data Analysis – Tutorial for Beginners series. Today I’ll show you some more advanced SQL moves! Though junior data…
Wouldn’t it be good to know where most of your traffic is coming from? What about email sign ups or even revenue broken down by social channels? How…
This is kind of a special blogpost, because here I share 3 videos from my brand new O’Reilly Video course – called Data Science Fundamentals for Marketing and Business…
Heatmapping is a simple and efficient way to analyze visitor interaction and user behavior on your website. If you are in a Conversion Rate Optimization (aka. CRO) project…
Combining tables is a key component, when you are doing data analysis. And SQL is really good at it! Of course each case is different, but I’ve run…
You have already learnt a lot about the basics of SQL for data analysis. I figured, it would be nice to have now an episode focusing only on…
Today I’ll show you the most essential SQL functions, that you will use for finding the maximums or the minimums (MAX, MIN) in a data set and to…
“How do I optimize Facebook campaigns?” This is the question that I hear all the time from clients to whom I teach Facebook marketing. Of course, it depends…
This is the second episode of my SQL for Data Analysis (for beginners) series and today I’ll show you every tiny little details of the SQL WHERE clause….
In my previous SQL for data analysis tutorial I’ve briefly mentioned, that I prefer SQL Workbench over pgadmin4 for SQL querying. Today I will show you, how you can install it…
SQL is a must, if you want to be a Data Analyst or a Data Scientist. I have worked with many online businesses in the last few years…
Smaller companies have smaller data teams (maybe just one person), bigger companies have bigger. The tricky thing is that the several aspects of a data project need several…
Usability testing is a widely used research method to collect detailed and direct qualitative user feedback about your product (or website, mobile application, anything…) What is it exactly…