# data preparation

### Recoding quantitative variables into qualitative ones – techniques and their practical application

When analyzing data, we consider both quantitative information (such as salary, age, number of products ordered) and qualitative...

### Population Pyramid

When looking for the best way to visualize the data you have, you may come across an impressively wide range of different types of...

### The Three-Sigma Rule

The three-sigma rule is an important tool in statistics and quality management. In the context of data analysis, it allows the...

### Segmentation: from grouping to classification

Segmentation is a key process in data analysis, dividing a data set into relatively homogeneous groups based on specific criteria....

### Outlier or anomaly? Detection of abnormal observations

Can one abnormal occurrence cause concern? Based on one deviation from the norm, should a red light start flashing? Of course! In...

### Statistical inference

Statistical inference is the branch of statistics through which it becomes possible to describe, analyse and make inferences about...

### Outlier cases. Identification and significance in data analysis

In data analysis, it is important to identify unusual observations that are significantly different from the others. Such values, called outliers or outlier cases, can affect the...

### Levels of measurement

The level of measurement is one of the most important properties of variables. It determines which statistical tests will be available to the researcher during the course of the...

### How to prepare for reliability analysis?

The area of reliability analysis is of interest first of all to those who plan to use scales and indices in their studies, namely more complex indicators than a single survey...

### Deciding to remove an item from the scale

Sometimes instead of asking a single question in a survey, we ask a whole set of questions, which are intended to be used later to build a scale.

### Data sourcing: pros and cons of desk research

Both business and science undertake research to survive and thrive. It is invariably a complex process that requires not only knowledge but also experience.

### Car value: Variable selection for linear modelling

The Automatic linear modeling procedure is intended to streamline the work of analysts who use regression models.