Last Updated on October 31, 2019 A common problem in applied machine learning is determining whether input features are relevant to the outcome to be predicted. This is the problem of feature selection. In the case of classification problems where input variables are also categorical, we can use statistical tests to determine whether the output variable is dependent or independent of the input variables. If independent, then the input variable is a candidate for a feature that may be irrelevant […]

Last Updated on August 8, 2019 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 skill scores is real or the result of a statistical fluke. Statistical significance tests are designed to address this […]

Last Updated on August 8, 2019 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 in applied machine learning. After completing this tutorial, you will know: The need for systematic discovery via controlled experiments. […]

Last Updated on August 8, 2019 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 that statistical methods are required to effectively work through a machine learning predictive modeling project. In this post, you […]

Last Updated on August 8, 2019 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, you will discover clearly why statistics is important in general and for machine learning and generally the types of […]

Last Updated on August 8, 2019 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 on the behavior of models and explainability of predictions. The very close relationship between the two approaches to the […]

Last Updated on August 14, 2020 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 area that is foreign to most developers and computer science graduates. This makes the chapter in Mitchell’s seminal machine […]

Last Updated on September 4, 2020 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 harnessing randomness is a required skill. In this tutorial, you will discover how to generate and work with random […]

Last Updated on August 8, 2019 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 intuition for the method or how to use it. Or it may be a playbook for a proprietary or […]

Last Updated on August 8, 2019 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 association between variables with a non-Gaussian distribution. After completing this tutorial, you will know: How rank correlation methods work […]