# Statistics

## Articles

### Trees that grow from tables

When stepping outside the domain of distributive and descriptive statistics for individual variable…

### Is gambling addictive? What if the respondent has no opinion?

The standard approach to investigating a single categorical variable involves a few elements.

### Three ways to perceive reliability

When measuring a phenomenon, you need to select the right tool. To measure temperature, you use a t…

### Reduction of multidimensionality

Is a simple two-dimensional coordinate system always enough for us?

### 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 in…

### 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 a…

### Perceptual maps: choosing the correct normalization method

In this article you can find perceptual maps prepared using different normalization methods.

### Correspondence analysis: solution quality assessment

Correspondence analysis is a technique often thought of as an alternative to a crosstab (contingenc…

### SNA or network as an analytical object

Today, we will look into Social Network Analysis (SNA), or Social Relation Analysis.

### How to boost a decision tree algorithm

The decision tree is a popular and effective algorithm used primarily in classification work, but i…

### Consumer shopping value analysis using regression trees. Part 1

How can we estimate the potential value of consumer shopping, predict the behavior of a visitor to …

### Car value: variable selection for linear modelling

The Automatic linear modeling procedure is intended to streamline the work of analysts who use regr…

### Automatic linear modeling: ensemble models

Today, we will look into ensemble model methods.

### Multidimensional scaling in brand positioning

Positioning a product in the context of the competition, or the identification of a product’s featu…

### Consumer shopping value analysis using regression trees. Part 2

Regression trees are a very interesting data analysis technique commonly used in tasks related to p…

### Scatter plot

A scatterplot (also otherwise known as a dot plot or scatterplot) is a graph with two perpendicular…

### Factor analysis

The aim of factor analysis is to explain as much of the variability as possible with as few variabl…

### The power of a test

The power of a test is the probability of detecting a statistically significant effect when one act…

### From variance to the method of least squares

The mean is one of the most popular and widely used statistical measures. By itself, it is not an e…

### Student T-tests

The Student's t-test group is used to compare two groups of results, measured by the arithmetic mea…

### Pearson's chi-square independence test

The chi-square test of independence is one of the most common statistical tests. It is used to test…

### Quantiles, quartiles, percentiles (measures of location)

We use quantiles to determine the position of a given value compared to others in a group or popula…

### Skewness and kurtosis

Kurtosis and skewness are measures of asymmetry that describe properties such as the shape and asym…

### Logistic regression

Regression is used to predict the value of the dependent (predictor) variable on the basis of the v…

### Gini index

The Gini index is a measure of the concentration of the distribution of a variable.

### Entropy

Entropy is a measure of disorder or uncertainty in a probability distribution.

### Pearson's chi-square correlation test

Popular statistical tests include Pearson's chi-square tests. It is worth noting at the outset that…

### Levels of measurement

The level of measurement is one of the most important properties of variables. It determines which …

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

In data analysis, it is important to identify unusual observations that are significantly different…

### Statistical inference

Statistical inference is the branch of statistics through which it becomes possible to describe, an…

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

When analysing the data, we take into account both quantitative information (such as salary, age, n…

### Segmentation: from grouping to classification

Segmentation is a key process in data analysis, dividing a data set into relatively homogeneous gro…

### The three sigma rule

The three sigma rule is an important tool in statistics and quality management. In the context of d…
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