How to assess the normality of a dataset in Python — Data scientists usually have to check if data is normally distributed. An example is the normality check on the residuals of linear regression in order to correctly use the F-test. Let’s see how we can check the normality of a dataset. What is normality? Normality means that a particular sample has been generated…

3 easy ways to compare the mean value of a sample with other, expected values — Data scientists and analysts often have to work with mean values and need to compare the mean value of a sample with a known expected value or the mean value of another sample. Statistics helps us with a powerful set of hypothesis tests we can perform for such tasks. The problem Let’s…

A simple introduction to hypothesis tests — Statistics is a data scientist’s best friend. Hypothesis tests are a family of very useful tools for any kind of analysis. They can really help us assess the statistical significance of some phenomena. However, we have to master such tools properly in order to benefit from their advantages. What is a hypothesis test? A hypothesis…

Dividend ETFs are a useful tool for investors. — In this article, the advantages and disadvantages of dividend ETFs are presented. An investor should look for bond-based ETFs in order to have a good dividend yield and avoid the risk related to stocks. A possible portfolio idea is then presented in order to help an investor make an idea…

A brief guide to creating your own simple expense manager application — I have always been looking for a simple expense manager app I could use with my wife to collect our daily expenses. This app should be a voice app that parses my voice and adds a line to a spreadsheet or something. Since I could never find something like that…

A simple tool for voice transcription — Recently, I stumbled upon a tool called AssemblyAI, which implements some APIs for speech recognition and analysis. I’ve decided to try it in order to create a small voice diary using Telegram, Python and Notion. What is a voice diary? The tool I’m about to create is a voice diary, which is a document with…

Some flaws of Principal Component Analysis that affect supervised machine learning projects — Principal Component Analysis is a very useful dimensionality reduction tool. It can really help you reduce the number of features of a model. Although it may seem a powerful tool for a data scientist, there are some drawbacks that I think make it unsuitable for supervised machine learning projects. What is PCA?

Let’s compare our model with a trivial baseline — Every time we train a model we should check if its performance beats some baseline, which is a trivial model that doesn’t take the inputs into account. Comparing our model with a baseline model, we can actually figure out whether it actually learns or not. What is a baseline model? A baseline model is a…

Some techniques to see if a dataset is imbalanced — Dealing with imbalanced datasets is always hard for a data scientist. Such datasets can create trouble for our machine learning models if we don’t deal with them properly. So, measuring how much our dataset is imbalanced is important before taking the proper precautions. …