Statistical hypothesis tests report on the likelihood of the observed results given an assumption, such as no association between variables or no difference between groups. Hypothesis tests do not comment on the size of the effect if the association or difference is statistically significant. This highlights the need for standard ways of calculating and reporting […]

# Archive | Statistics

## How to Calculate Nonparametric Rank Correlation in Python

Correlation is a measure of the association between two variables. It is easy to calculate and interpret when both variables have a well understood Gaussian distribution. When we do not know the distribution of the variables, we must use nonparametric rank correlation methods. In this tutorial, you will discover rank correlation methods for quantifying the […]

## Statistics in Plain English for Machine Learning

There is an ocean of books on statistics; where do you start? A big problem in choosing a beginner book on statistics is that a book may suffer one of two common problems. It may be a mathematical textbook filled with derivations, special cases, and proofs for each statistical method with little idea for the […]

## How to Generate Random Numbers in Python

The use of randomness is an important part of the configuration and evaluation of machine learning algorithms. From the random initialization of weights in an artificial neural network, to the splitting of data into random train and test sets, to the random shuffling of a training dataset in stochastic gradient descent, generating random numbers and […]

## Statistics for Evaluating Machine Learning Models

Tom Mitchell’s classic 1997 book “Machine Learning” provides a chapter dedicated to statistical methods for evaluating machine learning models. Statistics provides an important set of tools used at each step of a machine learning project. A practitioner cannot effectively evaluate the skill of a machine learning model without using statistical methods. Unfortunately, statistics is an […]

## The Close Relationship Between Applied Statistics and Machine Learning

The machine learning practitioner has a tradition of algorithms and a pragmatic focus on results and model skill above other concerns such as model interpretability. Statisticians work on much the same type of modeling problems under the names of applied statistics and statistical learning. Coming from a mathematical background, they have more of a focus […]

## What is Statistics (and why is it important in machine learning)?

Statistics is a collection of tools that you can use to get answers to important questions about data. You can use descriptive statistical methods to transform raw observations into information that you can understand and share. You can use inferential statistical methods to reason from small samples of data to whole domains. In this post, […]

## 10 Examples of How to Use Statistical Methods in a Machine Learning Project

Statistics and machine learning are two very closely related fields. In fact, the line between the two can be very fuzzy at times. Nevertheless, there are methods that clearly belong to the field of statistics that are not only useful, but invaluable when working on a machine learning project. It would be fair to say […]

## Controlled Experiments in Machine Learning

Systematic experimentation is a key part of applied machine learning. Given the complexity of machine learning methods, they resist formal analysis methods. Therefore, we must learn about the behavior of algorithms on our specific problems empirically. We do this using controlled experiments. In this tutorial, you will discover the important role that controlled experiments play […]

## Statistical Significance Tests for Comparing Machine Learning Algorithms

Comparing machine learning methods and selecting a final model is a common operation in applied machine learning. Models are commonly evaluated using resampling methods like k-fold cross-validation from which mean skill scores are calculated and compared directly. Although simple, this approach can be misleading as it is hard to know whether the difference between mean […]