0
votes
0answers
31 views

How to do multilevel classification using R

I am trying to do a multilevel text classification using R. Is there any package in R which I can use to do it? If not, then how can I proceed using the svm or ...
0
votes
1answer
50 views

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 ...
0
votes
0answers
27 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 ...
1
vote
1answer
31 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 ...
2
votes
1answer
77 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 ...
1
vote
0answers
31 views

R package kernlab probabilities seem not to match decision

For a classification problem I am giving the R package kernlab a shot – not the least because it offers to calculate class probabilities instead of only a plain decision. However, comparing results ...
0
votes
0answers
68 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 ...
4
votes
2answers
91 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 ...
0
votes
0answers
30 views

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 ...
1
vote
1answer
46 views

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?
1
vote
1answer
145 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. ...
1
vote
0answers
38 views

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. ...
0
votes
0answers
21 views

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 ...
3
votes
1answer
151 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 ...
1
vote
1answer
69 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 ...
2
votes
1answer
119 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 ...
1
vote
2answers
69 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 ...
0
votes
0answers
46 views

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 ...
0
votes
1answer
43 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 : ...
1
vote
1answer
171 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 ...
0
votes
0answers
23 views

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 ...
1
vote
1answer
40 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 ...
3
votes
1answer
196 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: ...
4
votes
1answer
133 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 ...
0
votes
1answer
191 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 ...
2
votes
3answers
547 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, ...
0
votes
0answers
30 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 ...
1
vote
1answer
88 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, ...
2
votes
1answer
98 views

How to draw ROC curve with three response variable?

I have a toy example reproduced below in which the response variable has three possible classes. I am trying to create an ROC but not sure how to deal with it when there are three classes. Any help ...
0
votes
0answers
41 views

Classification with Bayes Network (deal)

I am working with multiple binary vectors e.g., A,B,C,D,E,F,G,H. I want to find the classification between them. I have tried the following: ...
0
votes
0answers
68 views

What to expect from classification models

I am testing various classification schemes on a training set with about 3000 instances and 20 attributes. The train set is distributed into 6 classes such that the chance accuracy would be about 18%. ...
0
votes
1answer
63 views

Priors and Loss in R

I am fairly new to R and data mining concepts and am trying to understand the rpart package in R. I am a bit confused about the role of priors and loss in the ...
1
vote
1answer
110 views

Binary classification on imbalance data with missing values and almost equal dimensions?

I have a data set with following qualities: Attributes: 500 Instances: 1500 Class Ratio: 1:15 Missing Values: Yes ~5% How should I perform classification on ...
1
vote
0answers
28 views

Group Classification for uni-variate Data R

Given that I have some data for prices, and i have several prices groups, say, Data = [$15,$20,$20,$10,$15,$25,$20,$15] and Groups: ...
2
votes
1answer
175 views

SMOTE throws error for multi class imbalance problem

I am trying to use SMOTE to correct imbalance in my multi-class classification problem. Although SMOTE works perfectly on the iris dataset as per the SMOTE help document, it does not work on a similar ...
-1
votes
1answer
79 views

Classifying data in R [closed]

I'm using R and I want to use some type of machine learning technique (SVM, perhaps) to classify data. I have data that looks like this, for example ...
2
votes
0answers
74 views

What form of analysis should be used for loss given default estimates?

I am working on BASEL II IRB models and we have to estimate loss based on historic defaults. There are different outcomes/scenarios we have identified that a default can encounter that will affect ...
1
vote
2answers
125 views

Imputation of missing parameter value by regressing the other parameters

I have a question on imputation of missing values. A support vector machine does not work with missing values, and in practice i thus hence na.omit the rows / cases with missing values on any of the ...
1
vote
1answer
722 views

Random forest - binary classification vs. regression?

I have a dataset that I'm trying to classify into 2 groups, A and B, using a random forest model. I know the true grouping and I'm trying to see how well I can model it using the other available ...
0
votes
0answers
14 views

Reduce Sample Size (Categorise??) [duplicate]

I have been looking for an answer to my question but havn't been able to find any literature documentation or help in regards. I have a large dataset which I need to further analyse. Because of this I ...
3
votes
1answer
324 views

Can we use random forest for classification in combination with distance matrix between classes?

With a colleague, we are working on a dataset containing ~5000 continuous variables for 120 individuals belonging to 8 classes. We want to estimate the relative importance of each variable to explain ...
2
votes
1answer
210 views

Procrustes Analysis of 3d point cloud without defined landmarks

I am working with several hundred 3d point clouds generated using a 3d scanner and would like to be able to compare their shapes using something like a procrustes analysis. Instead of manually ...
0
votes
1answer
203 views

Fit of a normal distribution to a one-dimensional dataset in R

I've got a set of (continuous) values from a measurement, where each object should be either positive or negative, and I know that the values of the "negative" objects should be approximately normally ...
2
votes
0answers
265 views

SVM classifier (with soft-margin) implementation in R, gamma value and quadprog

I'm trying to implement a Support Vector Machine classifier in R and I have to solve the optimization problem using the quadprog R package which solves problems of the form : $$min_b \frac{1}{2} ...
0
votes
1answer
142 views

How to evaluate concordance between 2 raters and factors that affect the concordance

I have about 1000 subjects ($id$) and each of them has some baseline variables (demographic variables $X1, X2, X3, Xn$, which can be continuous, factors). Every subject is classified by two raters ...
0
votes
0answers
201 views

Obtaining final classification score using AdaBoost predict function

If I understand correctly, predict.ada() returns an $n$ by 2 matrix of class probabilities for each classifier used in $n$ iterations. How can I obtain the final classification on scale of [0,1] for ...
2
votes
0answers
57 views

How should I distribute a classifier to customers?

When consulting, I often do my exploratory analysis and prototyping in R, and deliver results on the initial dataset to the client. The client wants to use the trained classifier in a production ...
1
vote
0answers
100 views

Modeling spatial correlations with multilevel data

I have ~5M records of spatial polar coordinates (r and theta). These 5M records are from 400 different 'locations' that I have ~150 variables for (no NAs). I also have 1 binary variable used to flag ...
3
votes
1answer
149 views

Battery of random forest models for each class

I have a dataset which consists of roughly 40,000 observations grouped into 12 classes. I did a quick random forest run on a single split of 80% training and 20% testing (Dont bring up the discussion ...
0
votes
1answer
387 views

Errors fitting a Penalized Linear Model

I am trying to reproduce the results from this answer in CrossValidated with no luck. I keep getting an error when calling: ...