Data Science Stack Exchange Community Digest

Top new questions this week:

Explain notation in Bishop Eq 1.60

I’m starting to work through Bishop’s “Pattern Recognition and Machine Learning” book, and have run into unfamiliar notation. Eq. 160 is prefaced by saying “For this purpose, we shall …

notation

asked by Jolyon Score of 2 answered by bogovicj Score of 1

Interpreting Learning Curves of models

I need some help to understand if the models are overfitting and which of these we can consider “the best”. On the internet i only find simple examples with learning curves but in these …

machine-learning python machine-learning-model data-science-model overfitting

asked by SimoneA Score of 1 answered by Nicolas Martin Score of 1

99% accuracy in train and 96% in test is too much overfitting?

I have a binary classification problem, the classes are quite balanced (57%-43%), with a GridSearch with Random Forest Classifier I obtained the best hyperparameters and I applied the model to train …

machine-learning python machine-learning-model data-science-model accuracy

asked by SimoneA Score of 1 answered by Mohith7548 Score of 1

A classification problem

I have a set of objects, each of which can have (but doesn’t always exhibit) a set of properties. Properties are shared between objects, in the sense that different objects can have common properties …

classification scikit-learn naive-bayes-classifier

asked by bontchev Score of 1 answered by Brian Spiering Score of 0

Are Chi-square and ANOVA (f_classif) to select best features?

I have a binary classification problem (target 0 o 1), I have both variables continuous and categorical as features. I understood that about Chi-square i can use only categorical features to evaluate …

machine-learning python data-science-model chi-square-test anova

asked by SimoneA Score of 1 answered by Mohith7548 Score of 1

A good 4th Benchmark method to compare the performance of a novel Variable Selection Algorithm being evaluated

I am collaborating on a research project with a respected econometrician as a graduate student (although only in an MS program, not PhD program mind you) exploring the properties and comparing the …

machine-learning regression feature-selection research lasso

asked by Marlen Score of 1

How to compare $R^{2}$ of train and test data in a Deep Learning Neural Network Regression model?

I want to judge the goodness of my neural network regression model built using Keras Python Library. The problem is the following: from an input like (1000, 5000) so 1000 samples and each sample has …

neural-network keras scikit-learn regression score

asked by HelpNeederStudent Score of 1 answered by Dave Score of 1

Greatest hits from previous weeks:

What is the difference between bootstrapping and cross-validation?

I used to apply K-fold cross-validation for robust evaluation of my machine learning models. But I’m aware of the existence of the bootstrapping method for this purpose as well. However, I cannot see …

cross-validation evaluation

asked by Fredrik Score of 50 answered by cbeleites unhappy with SX Score of 54

How can I check the correlation between features and target variable?

I am trying to build a Regression model and I am looking for a way to check whether there’s any correlation between features and target variables? This is my …

machine-learning scikit-learn regression linear-regression

asked by user_6396 Score of 30 answered by JahKnows Score of 23

K-Means clustering for mixed numeric and categorical data

My data set contains a number of numeric attributes and one categorical. Say, NumericAttr1, NumericAttr2, …, NumericAttrN, CategoricalAttr, where …

data-mining clustering octave k-means categorical-data

asked by IgorS Score of 197 answered by Tim Goodman Score of 180

What is Ground Truth

In the context of Machine Learning, I have seen the term Ground Truth used a lot. I have searched a lot and found the following definition in Wikipedia: In machine learning, the term “ground …

machine-learning neural-network deep-learning

asked by Green Falcon Score of 45 answered by Neil Slater Score of 42

Removing strings after a certain character in a given text

I have a dataset like the one below. I would like to remove all characters after the character ©. How can I do that in R? …

r data-cleaning

asked by Hamideh Score of 25 answered by MASL Score of 29

What does “baseline” mean in the context of machine learning?

What does “baseline” mean in the context of machine learning and data science? Someone wrote me: Hint: An appropriate baseline will give an RMSE of approximately 200. I don’t get this. Does he …

machine-learning regression predictive-modeling terminology

asked by Meiiso Score of 28 answered by Carl Rynegardh Score of 31

ValueError: could not convert string to float: '���'

I have a (2M, 23) dimensional numpy array X. It has a dtype of <U26, i.e. unicode string …

python dataframe csv data-formats

asked by cappy0704 Score of 8 answered by cappy0704 Score of 2

Can you answer these questions?

DecisionTreeRegressor with criterion='poisson' not recognizing perfect separation

I created a minimal example of Poisson decision tree regression as such …

scikit-learn decision-trees

asked by Jason Hadinata Score of 1

Combining multiple ranked lists

Suppose I’m given two ranked lists, A and B, with each item in the lists being associated with a score: …

machine-learning machine-learning-model ensemble-modeling ranking learning-to-rank

asked by kevin_was_here Score of 1 answered by J_H Score of 0

Complex graphical representation based on monthly groups

I’m still fairly new to R, and am having some real issues turning a data frame into a graphical representation. I downloaded some data for house prices in the UK and stripped it down to just the …

r data-analysis rstudio

asked by Lexifir Score of 1 answered by Oxbowerce Score of 0