Questions tagged [classification]

Statistical classification is the problem of identifying the sub-population to which new observations belong, where the identity of the sub-population is unknown, on the basis of a training set of data containing observations whose sub-population is known. Therefore these classifications will show a variable behavior which can be studied by statistics.

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401 views

True and false discovery rate in variable selection

I have a question about how I can calculate true and false positive rate in a simulation study? I have seen some articles and thesis by different definitions. One of them is the following one: TPR=...
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261 views

How to utilize the output probabilities from a probabilisitic classifier?

Can anybody please explain that in simple words: how can we correctly use probabilities given by some classifiers along with the predicted class values? Let us consider some implementation of a Naive ...
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173 views

Significance index of unlabeled data prediction

I have a training set used to train an SVM classifier, the model found is used to predict a dataset of several unlabeled examples. I would like to know how to extract an index of the goodness of the ...
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1k views

How to quantify the significance of the difference between two z-scores? [duplicate]

I have one sample and several features. I calculate a z-score for various features, and for various combinations of features. Is there a way to quantify the significance of the difference between ...
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499 views

Can RBMs be used for feature selection / reduction?

I have a data set that's ~ 150R X 2000C and was curious if an RBM is appropriate in situation with this type of imbalance. It's a microarray and I'm looking at a 0/1 classification problem. I'd be ...
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194 views

Best way to classify hierarchical data

First of all, I want to be clear that I am new to AI, although I've learned a bit about classification. Let's say I have a hierarchical sets of words: ...
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138 views

Adding training examples to Bayesian classifier reduces accuracy

I'm working on a problem to predict/classify overall sentiment of a large amount of text, which I can verify on the next day. Each data point is a day and is composed of multiple articles. I bin the ...
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499 views

CART with rpart and a 12 level factor

I have a 12-level factor variable (month) in my dataset and I wanted to fit a CART tree with rpart(). Would you split the 12-level factor variable into 12 dummy variables? If I fit the model with one ...
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194 views

Problem with classifying new observations with discriminant analysis

I have a data set of 40,000 individuals which I clustered using k-means. I used 30 variables, each ordinal from 1=minimum to ...
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1answer
2k views

Using GPML in Matlab for MultiClass Classification

I am using Rasmussen's GPML code in Matlab R2011a_student. I have training data (2560x29707) w/ labels (6 classes), and test data (640x29707). To prep the data I have converted from sparse to full, ...
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855 views

LMNN: Simple Algorithm Description

B"H Hello, I understand the principles of LMNN (Large-Margin Nearest Neighbor) classification very well, but not all that well Weinberger's pseudo-code for its implementation. Can anyone simply (but ...
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62 views

Classifying new observations into two bivariate categories

I have two bivariate distributions $A$ and $B$. For some new observation $x$, I would like to calculate the probability that it belongs to $A$ and not $B$. I can assume that $A$ and $B$ are ...
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720 views

What is the appropriate method to use to calculate customer lifetime value?

I'd like to figure out what the potential lifetime value of a customer may be based on their purchasing patterns with our products. I have transactional data that tells me what a customer purchased, ...
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1answer
20 views

Should Learning Curves be Plotted only on Train or the Entire Dataset?

In order to compare a few models to start my ML project, first I split the dataset into train and test, and then performed nested CV on the training set only and got my fair estimate of true risk on ...
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1answer
280 views

Best Suitable feature selection method for ordinal logistic regression

I have 33 variables my dataset, I need to omit some less significant features then, which is the "best suitable feature selection method " for the Ordinal Logistic Regression?
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1answer
399 views

Cross Validation with duplicates and (un)balanced data

I am currently working on a student project were we do a binary classification. But the data is highly screwed! The train AND test data contains a huge amount of duplicates , were every row is ...
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1answer
197 views

One class of Ordinal DV values has too few observations - best way to address

I am doing an ordinal classification using glmnet, with 3 level class DV: 1 (bad), 2(ok), 3(good). I am trying to fit a model to this ordinal DV, and find best features. The problem is that one of the ...
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1answer
293 views

Linear regression for binary classification - a new classifier

I am new to classification, but not to regression. I already used regression to fit a linear combination of time varying signals to match two constant signals, -1 and 1, representing their classes. ...
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1answer
81 views

Anomaly detection

I am trying to categorize the functionality of batteries in one kind of device. I am using linear models to find the functionality of batteries over time (considering other variables in the device ...
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1answer
326 views

Recommended multiclass classification algortihms for this particular problem

I'm using this dataset, https://archive.ics.uci.edu/ml/datasets/Drug+consumption+%28quantified%29, in a research whose main goal is to find correlations among attributes that influences people to be ...
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1answer
1k views

Xgboost cv evaluation metric - unbalanced data

I'm using Xgboost for some binary classification and so it makes sense for me to use log loss as my evaluation metric within cross validation. My data is highly unbalanced though. Would log loss ...
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1answer
605 views

Comparing supervised text classification algorithms with unlabeled documents from web

Working with the unlabeled documents from web for supervised text classification, even though the problem settings dictates using semi-supervised learning, I aim to compare several different ...
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1answer
2k views

Interpreting log-loss as percentage

I know that log-loss penalises models that are confident with the wrong predicted classes. Can this be translated to percentage accuracy? If not, then how do I report the error or compare it to other ...
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1answer
39 views

which of these 2 classification models is best

The difference between the two models is the label, which is slightly differently defined for the 2nd model. So for model 2 there are less data that fall in class 1.0 (87161 versus 155915). Which of ...
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1answer
432 views

converting discrete values to buckets to perform predictions

I have a set of continuous discrete values, which I would like to convert to a classification task. Say, my scores in an exam are anything between 0-100. I want to convert my scores in the next exam ...
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1answer
155 views

Content-control (web filtering) using machine learning

I'm trying to build a content-control (web filtering) application using machine learning (just for training purposes). For example define gaming sites. I'm somewhat familiar with machine learning ...
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1answer
874 views

How to do a classification with only one variable? [duplicate]

I would like to classify individuals of a database by a single quantitative variable. Is hierachical clustering suitable to do this? If it is possible, how the algorithm work? If use hierachical ...
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1answer
1k views

What are the benefits for semi-supervised learning over unsupervised clustering? Or any limitations?

I have another question about semi-supervised learning vs unsupervised clustering, what are the benefits and limitations? I have got some data with labels and some without labels. I performed semi-...
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1answer
2k views

Classification and mixed categorical and numeric variables

I've been working a little with weka and so far I haven't made my own database to apply a classifier but I've tried to look at the already existing files and from what I've seen there is absolutely no ...
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2answers
250 views

Is classifying documents according to their topic useful for any application? [closed]

Suppose that we have digitized document images; we pass this documents through OCR and we get text text documents, that we classify according to their topics in different classes such as payroll, ...
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1answer
56 views

Why fewer feature classification models can perform better?

I have seen articles on the “curse of dimensionality” and why reducing the number of features can help with overfitting, but imagine we are interested in cases with significantly less features. Why is ...
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1answer
866 views

Which machine learning algorithms can do multi-categories classification? [closed]

as a ML Newbie, I'm interested in which machine learning algorithms can do multi-categories classification? Are there different techniques for fewer categories (3) and more categories? And what are ...
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1answer
52 views

How to form clusters when features are sets of string objects

I am building a movie recommender. But unlike common recommender from movielens data, features of my movies are sets like actor list, genre list, list of producers and writers etc. I know I can use ...
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1answer
243 views

How can I use SVM or Logical Regression on polynomial class labels?

I was told that SVM would return good results for my research task, but afaik SVMs and Logical regression work with binomial class labels. How can I make them work with classes that have more than ...
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2answers
142 views

Which neural network would you fit for this problem?

I have the following dataset that constitutes of four attributes that I can use for classification of objects. I know that there are two classes of objects from this dataset but I do not have target ...
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4answers
2k views

Multi-label classification

I am working on a project and I need some suggestions. I have a data set with 600 songs and for each song we have 60 numerical features (linked to the rhythm and the timbre of the sound). Moreover ...
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2answers
136 views

How do we analyse likelihood in a dataset? [closed]

I am working to analyze poverty rate using census data. I have a huge dataset. I want to extract the likelihood from this dataset in order to create patterns for energy consumption. What is the ...
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1answer
875 views

bag of words in an online configuration, for classification / clustering

I have a set of image documents. I extract text keywords from this images using OCR to represent each image as a bag of words (a vector where each value is the number of occurrence of a word in the ...
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3answers
81 views

Tricky Interview Question [closed]

I was recently given an interview, and given the following scenario: You have one classification problem to solve. You can use either of the following 1) linear regression algorithm 2) Neural ...
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1answer
317 views

My neural network will run okay, but occasionally (every 1000) it provides an error. [closed]

I am using a neural network to forecast the direction of gold prices. I have created a neural network neuralnet within R. My programme runs well and i can get a prediction accuracy of about 51%. ...
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1answer
37 views

Classify strings having centers already found in python? [closed]

On StackOverflow suggested me to ask this question here. I'll copy it. I have a list of binary strings and two center strings which are not in the list. I would like to classify that list around the ...
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1answer
609 views

Multiple digits MNIST and transfer learning [closed]

I have a sample of 50,000 images, some of which are shown below: $\qquad$ $\qquad$ $\qquad$ $\qquad$ Associated to these images are labels for the digit with the largest pixel size. My goal is ...
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1answer
217 views

How to interpret the ROC curve on a binary classifier that always predicts 0?

Suppose we have a binary classifer that always chooses 0 no matter what. In this case, the ROC curve will be a horizontal line with AUC equal to 0.5. My question is, if we have such a curve, does it ...
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1answer
110 views

How could the result of a decicion tree (maximum depth) be converted to probabilities

I would like to compute a ROC-Curve for a decision tree created with sklearn based on the CART algorithm. Logically, if I compute it with maximum depth I always get a probability of 1 or 0 (discrete ...
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1answer
445 views

the accuracy formula of classification using lda

what is the formula of accuracy linear discriminant system as classifier? is the multi class and 2 class have same formula of accuracy? i tried to find it in google but cant find one, help me please ...
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1answer
650 views

Accuracy of K Nearest Neighbor in near-ties

Suppose you have a case where there's a near-tie in K Nearest Neighbor Algorithm - 3 of the K Nearest Neighbors are in class A and 2 of the K Nearest Neighbors are ...
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1answer
519 views

Imbalance Classification : How SMOTE handles majority class?

I'm working on Imbalance Classification problem with minority class(0.017%). I've read that imbalance classification can be handled using Undersampling, Oversampling and SMOTE. Major drawback of ...
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1answer
2k views

When would it be appropriate to use CNN vs. DNN?

I guess the common rule of thumb when choosing between CNN vs. DNN is if it has to do with images choose CNN and data points for DNN. But what if input images are pretty small.. in my case (33,45,3)...
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1answer
30 views

Is applying Clustering and then Classification good approach to solve multi-categorical classification problems?

Like for following Data Example: Let's assume I have following T-Shirt size categories: Training Data set: ...
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1answer
34 views

Classifying 8 objects based on 3 attributes [closed]

I had 8 objects and asked 80 people to score them on three attributes, say A, B, and C. Now I want to check if these 8 objects can be classified into categories based on the similarity between the ...