## How not to show data on a π chart

In this article, we’ll take a look at some of god-awful charts and hopefully learn a thing or two about good data visualization.

## New Vertabelo Academy Course on Data Visualization: Share Your Insights With Everyone!

In today’s data-driven world, a good visualization goes a long way in helping people make sense of numbers. Every day at the office, we’re working hard to create programming and data science content that is accessible to everyone. We aim to produce content that is easy to understand, primarily for people with no IT background. And you know what? Ironically, this stuff ain’t easy even if you’re an IT specialist! We seek metaphors and real-life applications; we share our experience

## High-Performance Statistical Queries: Dependencies Between Discrete Variables

In my previous article, we looked at how you can calculate linear dependencies between two continuous variables with covariance and correlation. Both methods use the means of the two variables in their calculations. However, mean values and other population moments make no sense for categorical (nominal) variables. For instance, if you denote “Clerical” as 1 and “Professional” as 2 for an occupation variable, what does the average of 1.5 signify? You have to find another test for dependencies—a test that

## High Performance Statistical Queries –Skewness and Kurtosis

In descriptive statistics, the first four population moments include center, spread, skewness, and kurtosis or peakedness of a distribution. In this article, I am explaining the third and fourth population moments, the skewness and the kurtosis, and how to calculate them. Mean uses the values on the first degree in the calculation; therefore, it is the first population moment. Standard deviation uses the squared values and is therefore the second population moment. Skewness is the third, and kurtosis is the

## High-Performance Statistical Queries in SQL: Part 2 – Calculating Centers of Distribution

My previous article explained how to calculate frequencies using T-SQL queries. Frequencies are used to analyze the distribution of discrete variables. Today, we’ll continue learning about statistics and SQL. In particular, we’ll focus on calculating centers of distribution. In statistics, certain measurements are known as moments. You can describe continuous variables (i.e. a variable that has a large range of possible numbers, such as household incomes in a country) with population moments. These moments give you insight into the distribution