# Tagged Questions

12 views

### Optimal classification model for translating words

I have the following problem: I have a set of English words which I want to translate to Dutch. Of each words I mined a set of possible translations. For example, for the word "Eighteen" I obtained ...
25 views

### Sample Weights for classification using Gradient-Boosted trees?

How can "weights" be given to different samples according to their relative importance while using Gradient boosted decision trees for classification? How does the ...
43 views

### Bayes' classification in R

For a machine learning class I am taking, on our first homework assignment we are given the following problem that has me stuck: ...
70 views

### How to change threshold for classification in R randomForests?

All the Species Distribution Modelling literature suggests that when predicting the presence/absence of a species using a model that outputs probabilities (e.g., RandomForests), choice of the ...
34 views

### R regression with categorical response variable

I have four variables, two are categorical and two are numeric: ...
109 views

### Reproduce linear discriminant analysis projection plot

I'm struggling with projection points in linear discriminant analysis (LDA). Many books on multivariate statistical methods illustrate the idea of the LDA with the figure below. The problem ...
27 views

### Conditional Inference trees on correlated observations

I have a dataset containing a binary response variable and a few numeric predictor variables. I would like to use Conditional Inference Trees algorithm in R using the ctree function in party package. ...
37 views

### logistic regression using probabilities of class labels

My goal is to train a logistic classifier. My samples in my dataset have some label noise but for each label I can give a probability how correct this label is. What is the best way to incorporate ...
31 views

### Entire data considered as support vector

I am currently learning to use support vector machine as classification. I have a data set with 161 observation and 18 dimension. I get 160 support vectors using svm function form R package, e1071. ...
86 views

### calculating probability or filtering that certain subject is not in the particular cluster

I have a situation where there are n individuals and p features (variables). I do have their cluster information. Here is an example: ...
37 views

### Using proper scoring rule to determine class membership from logistic regression

I am using logistic regression to predict likelihood of an event occurring. Ultimately, these probabilities are put into a production environment, where we focus as much as possible on hitting our ...
63 views

### test validation versus k-fold cross validation

I am attempting to use a neural network, after using other machine learning algorithms. I am using the RSNNS package (I am willing to use / evaluate other packages) that's part of R. I would like to ...
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### Maxent Markov models in R

Is there a package that implements Maxent Markov Models in R? (http://en.wikipedia.org/wiki/Maximum-entropy_Markov_model). I understand that package crf implemets conditional random fields which are ...
32 views

### visualize the naive bayes with k-fold cv

I have done the classification using naive Bayes as a classifier, and applied 10-fold CV.I know that I can get the mean and variance of the result. However, how can I plot the classifier performance? ...
76 views

### Way to train Hidden Markov Model in R with multiple sequences

i have multiple sequences for each of two states. I'd like to train a HMM with these to predict the state for unkown sequences. Here is an example for this problem: ...
78 views

### Best feature selection method for naive Bayes classification

i want to make classification with naive Bayes. I have got about 100 Features. Numerical ones as well as categorical ones. Since i want only the most relevant ones to be included for the ...
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### construct/load dataset that performs better with diffusion kernel than other kernel

I'm looking for a dataset on which a diffusion kernel (also called heat kernel), used via SVM, would get better accuracy than other kernels for the classification task. I want to use such a dataset to ...
40 views

### Hierarchiqual prediction using R

I'm pretty new in R, and I couldn't find any information about a package who can do the following: supposing that I have a set of data (for instance, different text documents), which can have several ...
33 views

### Multivariate Multiple Classification

Is it possible to have multiple (at least 3) dependent variables in a single classification model. I know this can be accomplished in a regression model but I need to perform this with a ...
135 views

### Evaluating accuracy of binary logistic regression on skewed data

I've been having an argument with a friend of mine, and it's very possible I'm wrong here. We are performing binary logistic regression on a dataset with 10000 observations, classifying action as ...
34 views

### Some Basic things we need to do when we are doing text classification

I am working on a project where I have to do multi-label text classification. I want to understand that whether my approach is correct or I am missing something. I am using R to do it. Clean ...
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### I want to learn about ROC curve — what is the canonical textbook?

I want to learn about Receiver-Operator-Characteristic curves, and metrics. I have read through online webpages with some basics, and I have used MATLAB built-ins to create ROC plots. It tells me ...
34 views

### how to compute odds ratio

Given a generic classification model $y=f(x_1,x_2,..,x_p)$ where $y\in \left\lbrace 0,1 \right\rbrace$ is it possible to compute the odds ratio for each variable? A theoretical explanation and ...
175 views

### How to implement a hold-out validation in R

Let's say I'm using the Sonar data and I'd like to make a hold-out validation in R. I partitioned the data using the createFolds ...
290 views

### Relative importance of a set of predictors in a random forests classification in R

I'd like to determine the relative importance of sets of variables toward a randomForest classification model in R. The ...
57 views

### R package kernlab probabilities seem not to match decision

For a classification problem I am giving the R package kernlab a shot â€“ not the least because it offers to calculate class probabilities instead of only a plain decision. However, comparing results ...
111 views

### Pattern Recognition in Practical Problem in R

I am using R for last 4 months with basic test analysis, regression models, ANOVA etc. Now I am looking into a particular problem. In words problem can be stated like, A particular machine got a ...
127 views

### What's the easiest way to separate two populations in a scatterplot?

I have to separate two populations by a line in a scatterplot: I would like find a threshold that separates the two populations. In @Waynes words, I would like to cluster the points into two ...
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### Which diffusion of latent Dirichlet allocation is helpful for assign the words corresponds to each topic?

In my corpus documents I have two different subjects. Which diffusion of LDA (asymmetric or symmetric) could help for assigning the words corresponds to Subject 1 and Subject 2 in my Topics? Here is ...
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### Divergence measure of two classifiers' performance?

I have two classifiers built with the same data. How can I measure divergence of these models? I found something like DIC but I don't know how to calculate this in R?
852 views

### Accuracy rate in naive Bayes classification

I am trying to use a naive Bayes classification technique to predict fraudsters (Caller). My training set of 138 instances has 5 columns viz. ...
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### Classifier predicts only one class

I was trying myself in kaggle CIFAR competition, I trained lots of classifiers but get the same result/fail (don't know how to treat them), maybe someone could help me figure what i'm doing wrong. ...
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### Classification model that allows changing priors at prediction time

I would like to know if there's a way to build a classification model in R that would allow me to change the class weights at prediction time. The scenario where I would want to do this: I have a ...
678 views

### Understanding the output of C5.0 classification model using the CARET package

The C5.0 classification model was used in this 4-class problem data with $N_{train}$=165, $P$=11, using caret R-package by ...
176 views

### Image classification using histogram

My apologies for another stats beginner question. This feels like reinventing the wheel, unfortunately I just can't find the answer myself. Googling "average densities classification" does not help ...
230 views

### How to interpret this cross-validated sparse LDA figure using CARET package?

Training data with $p$ =11 predictors and $n$ =165 with 4-class problem was cross-validated (5 times repeated 10-fold CV) using the sparse LDA (aka SDA) using caret ...
179 views

### Weighting more recent data in Random Forest model

I'm training a classification model with Random Forest to discriminate between 6 categories. My transactional data has approximately 60k+ observations and 35 variables. Here's an example of how it ...
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### multiple time series classification using randomForest R

I have daily time series of all constituent stocks/members of the S&P500, over a 5 yr horizon, and wish to classify as to whether a stock will report an "earnings revision" via a binary outcome ...
75 views

### Using regression forest for a factor variable

I want to predict if a customer is interested in a new product and I use the randomForest package for that. Target variable : factor (Yes or No) so I use the randomForest for classification : ...
669 views

### What is the best strategy to train and validate classification using PLS-[classifier] in caret package?

I have 4 clusters (see plot below) extracted from data of medical samples N=218 measured for 11 genes/predictors P=11 by this ...
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### Representing a class by negative number for training in GBM in R

I have already generated a huge train file of ~1GB in which the ground truth is one of 4 classes {-1,0,1,2}. Yes, I agree that I could have done it using 3 instead of -1, but for some conventional ...
41 views

### Estimate duration using categorical data

I have a dataset of tasks. Each task: has a duration (difftime in seconds) belongs to a project (project name factor) has an owner (user name factor) In R , I can simulate my data by something ...
404 views

### Can Random Forests do much better than the 2.8% test error on MNIST?

I haven't found any literature on the application of Random Forests to MNIST, CIFAR, STL-10, etc. so I thought I'd try them with the permutation-invariant MNIST myself. In R, I tried: ...
187 views

### 2D binary classification

Background A laboratory wants to evaluate whether a certain form of gel electrophoresis is suited as a classification method for the quality of a certain substance. Several gels were loaded, each ...
373 views

### random forest classification in R - no separation in training set

Originally posted on Stack Overflow, but suggested to move here... I'm new to machine learning, but I've tried to perform a Random Forest classification (randomForest package in R) on some ...
809 views

### Logistic regression: maximizing true positives - false positives

I have a logistic regression model (fit via glmnet in R with elastic net regularization), and I would like to maximize the difference between true positives and false positives. In order to do this, ...
42 views

### Minimizing Specificity in Adaboost (and other) Classifiers

This is a relatively simple question, but is not addressed in the documentation for the ada package in R. How do I go about instructing ...
139 views

### How bagging on CART (RPART) is different from CART with cross validation?

I am wondering is there any difference between the following two algorithms: RPART (Recursive partitioning) in R, with cross-validation (xval = 10, default) Bagging on RPART In the first case, ...