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 Statistical Learning


Regression (LR and MLR) and differences, not for the Economy. Professional analyst should be able to answer these three questions.

@machinelearnbot

To produce a regression analysis of inference that can be justified or trustworthy in the sense that helpful. The term in the statistical methods that generate a linear the best estimator is not bias (best linear unbiased estimator) abbreviated BLUE. Then there are some other things that are also important to note, in which the data to be processed, must meet certain requirements. Must meet the assumptions of single colinearity, meaning between independent variables with each independent variable others in the regression model no multicollinearity, is a condition where there is a linear relationship was perfect or near perfect between the independent variables. Must meet homoscedasticity assumptions, it means a state where the variance the existing data on every variable must be the same (constant).


10 types of regressions. Which one to use?

@machinelearnbot

Linear regression: Oldest type of regression, designed 250 years ago; computations (on small data) could easily be carried out by a human being, by design. Can be used for interpolation, but not suitable for predictive analytics; has many drawbacks when applied to modern data, e.g. A better solution is piecewise-linear regression, in particular for time series. Logistic regression: Used extensively in clinical trials, scoring and fraud detection, when the response is binary (chance of succeeding or failing, e.g. for a new tested drug or a credit card transaction). Suffers same drawbacks as linear regression (not robust, model-dependent), and computing regression coeffients involves using complex iterative, numerically unstable algorithm.


How to choose machine learning algorithms

#artificialintelligence

The answer to the question "What machine learning algorithm should I use?" is always "It depends." It depends on the size, quality, and nature of the data. It depends what you want to do with the answer. It depends on how the math of the algorithm was translated into instructions for the computer you are using. And it depends on how much time you have. Even the most experienced data scientists can't tell which algorithm will perform best before trying them. The Microsoft Azure Machine Learning Algorithm Cheat Sheet helps you choose the right machine learning algorithm for your predictive analytics solutions from the Microsoft Azure Machine Learning library of algorithms.


A simple neural network with Python and Keras - PyImageSearch

#artificialintelligence

In today's blog post, I demonstrated how to train a simple neural network using Python and Keras. We then applied our neural network to the Kaggle Dogs vs. Cats dataset and obtained 67.376% accuracy utilizing only the raw pixel intensities of the images. Starting next week, I'll begin discussing optimization methods such as gradient descent and Stochastic Gradient Descent (SGD). I'll also include a tutorial on backpropagation to help you understand the inner-workings of this important algorithm.


When Does Deep Learning Work Better Than SVMs or Random Forests?

@machinelearnbot

Guest blog by Sebastian Raschka, originally posted here. If we tackle a supervised learning problem, my advice is to start with the simplest hypothesis space first. I.e., try a linear model such as logistic regression. If this doesn't work "well" (i.e., it doesn't meet our expectation or performance criterion that we defined earlier), I would move on to the next experiment. I would say that random forests are probably THE "worry-free" approach - if such a thing exists in ML: There are no real hyperparameters to tune (maybe except for the number of trees; typically, the more trees we have the better).


I'd Rather Predict Basketball Games Than Elections: Elastic NBA Rankings

#artificialintelligence

The Elastic NBA Team Rankings is based on statistical modeling techniques frequently used across various industries to predict bankruptcy, fraud or customer buying behavior. No qualitative data or judgment is used to decide the ranks or the importance of different variables; the only human judgment applied is the underlying framework and features behind the algorithm.


Understanding Linear Regression

@machinelearnbot

Abstract: Although Linear Regression is arguably one of the most popular analytical techniques, I believe it isn't understood well. Several fundamental assumptions are violated during application. The objective of this note is to provide an overview of the assumptions and possible fixes. Linear regression is arguably one of the most widely used techniques in the data science world. But, a comprehensive understanding of this technique is not universal and it is at a level that is less than desired.


Unified Scalable Equivalent Formulations for Schatten Quasi-Norms

arXiv.org Machine Learning

The Schatten quasi-norm can be used to bridge the gap between the nuclear norm and rank function, and is the tighter approximation to matrix rank. However, most existing Schatten quasi-norm minimization (SQNM) algorithms, as well as for nuclear norm minimization, are too slow or even impractical for large-scale problems, due to the SVD or EVD of the whole matrix in each iteration. In this paper, we rigorously prove that for any p, p1, p2>0 satisfying 1/p=1/p1+1/p2, the Schatten-p quasi-norm of any matrix is equivalent to minimizing the product of the Schatten-p1 norm (or quasi-norm) and Schatten-p2 norm (or quasi-norm) of its two factor matrices. Then we present and prove the equivalence relationship between the product formula of the Schatten quasi-norm and its weighted sum formula for the two cases of p1 and p2: p1=p2 and p1\neq p2. In particular, when p>1/2, there is an equivalence between the Schatten-p quasi-norm of any matrix and the Schatten-2p norms of its two factor matrices, where the widely used equivalent formulation of the nuclear norm can be viewed as a special case. That is, various SQNM problems with p>1/2 can be transformed into the one only involving smooth, convex norms of two factor matrices, which can lead to simpler and more efficient algorithms than conventional methods. We further extend the theoretical results of two factor matrices to the cases of three and more factor matrices, from which we can see that for any 0


Layered Adaptive Importance Sampling

arXiv.org Machine Learning

Monte Carlo methods represent the "de facto" standard for approximating complicated integrals involving multidimensional target distributions. In order to generate random realizations from the target distribution, Monte Carlo techniques use simpler proposal probability densities to draw candidate samples. The performance of any such method is strictly related to the specification of the proposal distribution, such that unfortunate choices easily wreak havoc on the resulting estimators. In this work, we introduce a layered (i.e., hierarchical) procedure to generate samples employed within a Monte Carlo scheme. This approach ensures that an appropriate equivalent proposal density is always obtained automatically (thus eliminating the risk of a catastrophic performance), although at the expense of a moderate increase in the complexity. Furthermore, we provide a general unified importance sampling (IS) framework, where multiple proposal densities are employed and several IS schemes are introduced by applying the so-called deterministic mixture approach. Finally, given these schemes, we also propose a novel class of adaptive importance samplers using a population of proposals, where the adaptation is driven by independent parallel or interacting Markov Chain Monte Carlo (MCMC) chains. The resulting algorithms efficiently combine the benefits of both IS and MCMC methods.


Data Scientists Automated and Unemployed by 2025!

@machinelearnbot

In a recent poll the question was raised "Will Data Scientists be replaced by software, and if so, when?" Are we really just grist for the AI mill? As part of the broader digital technology revolution we data scientists regard ourselves as part of the solution not part of the problem. But as part of this fast moving industry built on identifying and removing pain points it's possible to see that we are actually part of the problem. Seen as a good news / bad news story it goes like this. The good news is that advanced predictive analytics are gaining acceptance and penetration at an ever expanding rate.