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 ...

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2 views

Anomaly Analysis (K-Means) - finding suspicious activities/operators

i am relativly new to the field of data mining and want to make a anomaly detection on transactional retail data. I want to use a simple anomaly detection (kmeans at the moment) for finding suspicious ...
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14 views

What is cross classification?

I could not find a Wikipedia page, can someone explain to a non-statistician what cross classification is? An example where this technique is used in financial risk assessment (credit risk / market ...
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36 views

How to combine weak classfiers to get a strong one?

Let as assume that we have a binary classification problem. We also have several classifiers. Instead of assigning a vector to a class (0 or 1) each classifier returns a probability that a given ...
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19 views

How to exploit relationships between independent variables?

Data: Each instance (representing a document) is a bag-of-entities (like BOW, except they're Wikipedia entities instead of words), so each feature is a binary or tfidf-like score based upon the ...
3
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0answers
38 views

Decision boundary in multivariate naive Bayes

This is from a sample exam for which I do not have the solutions. The question as stated is: True or False: The multivariate Gaussian naive Bayes always has a linear decision boundary. Explain ...
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1answer
30 views

SVM parameter tuning for unbalanced classes (with class weights)

I am trying to run an SVM on an imbalanced dataset (0-90%, 1-10%) using the e1071 package, with the radial kernel. I am using cross-validation to select the best gamma and cost. Additionally, I want ...
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1answer
37 views

Can regression be used in with 3 observation and more than 3 independent variable?

I want to regress v1 on o1:o7. I would like to do the same for each of v2:v5 with ...
3
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1answer
60 views

What's the meaning of dimensionality and what is it for this data?

I'm doing my assignment for my "Modeling and Optimization" course, and now I have doubts on the first question: What is the dimensionality of the data? What are the min, median, max, mean, ...
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11 views

Radial Basis Function Networks for Classification

I'm thinking of implementing a radial basis function network for a multinomial classification problem. Is there any benefit to this over using gaussian mixture modeling? Are they essentially the same ...
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2answers
43 views

Classifer for unbalanced dataset?

Is there any classifer that can natively support unbalanced datasets? Or what best practices you can suggest to handle such datasets? For example I want to solve task called "pedestrian detection" ...
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7 views

Merging two different segmentation solutions into one

I have the following problem: two different segmentation analysis to do, one using needs/motivations for consuming a product and one related to general attitudes toward product category and lifestyle. ...
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1answer
26 views

Robust softmax solutions for Theano?

I am implementing multilayer perceptrons with the softmax activation function over Theano. In some extreme cases I am running into problems with too high/low values in the softmax function that ...
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2answers
12 views

Prediction of n class variables

I have a historical data that has discrete variables. Let say I have data points with class labels 1, 2,3,4,5. For a given classification problem, I can use the training data and then get the trained ...
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15 views

Map of activated brain regions for special feature extraction method

I have read the following paper: "Feature Extraction for fMRI-Based Human Brain Activity Recognition". The most useful point for me is the new method of extracting features from fMRI images. It ...
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0answers
18 views

set SVM parameter range values for tuning [duplicate]

I am newbie to using svm for classification. I want to tune svm parameters by .TrainAutofunction in EmguCV. But I don't know what are the range(min-max value) of below parameters that I should give to ...
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1answer
14 views

How to interpret concretely the misclassification error?

I'm reading about Cart classification with rpart on R, and after all we should compute the misclassification error, given that y is the column that stocks classes, and x is the variable columns and ...
3
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2answers
41 views

Does it make sense to generate prediction intervals for the estimates of a logistic regression?

Say I have a binary outcome of 0 or 1 and suppose I were to use logistic regression model to estimate the probability a new sample will have an outcome of 1. I have read answers (for example here: ...
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0answers
16 views

Statistically compare differences between output probabilities of two trained models

I'm using two classification models that compute output probabilistic for my out-of-sample data (MLP and SVM). I want test that ...
0
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1answer
18 views

Training data set size and SVM classifier

I want to do a multi-class classification of human action recognition. I plan to collect data. So, How can I estimate the minimum data set size. What are the important parameters?
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0answers
12 views

What are valid ways of analysing predictors for a response variable that changes with time?

I have a cohort of similar patients who are likely to get a certain disease over time. I am trying to find out how some continuous health markers (e.g. weight) at time 0 are related to their disease ...
2
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17 views

Knowing precision on one data set, can I make claims about precision on another?

I am building a spam classifier for email. Let's say I have 3 million emails and I have a hypothesis that 1% of them are spam. So, I expect 30,000 of these 3 million emails to be spam but I don't ...
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0answers
10 views

Classifier for mixed data points

I have a dataset looking like this: Item: 1 -> Label: 50, Score: 0.0015272063901647925, FALSE Item: 2 -> Label: 50, Score: 0.012096011079847813, TRUE Item: 3 -> Label: 50, Score: ...
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0answers
10 views

Evaluation of features, how to find which feature is the most effective?

My question is following, which approach should i use in order to make a evaluation of features. To be more specific, for example we have a tweet message: "The weather is nice outside, it makes me ...
2
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0answers
9 views

How to chose the limit of speed for a stop

I have mouse events data(mouse events are generated when the mouse is moving). What would be the best way to calculate when the mouse is stopped? I see two cases: for ...
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1answer
50 views

MLP: Classification vs. Regression

Abstract I am teaching myself about NNs for a summer research project by following an MLP tutorial which classifies the MNIST handwriting database. I want to change the MLP from classification to ...
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5 views

Factorial Design with Completely randomized Design [closed]

A researcher conducted an experiment to determine the effects of 4 different pesticides on the yield of three varieties of citrus. Eight trees from each zariety were randomly selected from an orchard. ...
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2answers
27 views

What are some models that performs like Linear Discriminant Analysis?

I am interested in knowing what are some of the models that perform like Linear Discriminant Analysis which takes a combination of variables that best explain the data? I have a data set where some of ...
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2answers
31 views

How to find similar documents in a big data set

I have many text text documents and my goal is to find similar documents. Apparently it is a clustering type of question and LDA (Latent Dirichlet Allocation) is a good candidate to do that. However ...
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20 views

Assign the tree species most representitive of a specific size class

I am replicating another study in which trees were assigned to a class based on diameter. The most representative species of each class was identified for each plot sampled. The classes are sapling ...
0
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1answer
19 views

multi-class logistic regression for ordered labels

I have a set of labells: A - no lesion B - mild C - severe If an instance from a class predicted as its nearest class not a big problem ...
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0answers
38 views

convert 20 category problem into a set of pairwise classifcations

i am struggling to convert a 20 category problem into a set of pairwise classifications. I have separated the categories into 4 classes and calculated the size of the set to be 60. Total = (k-1) x n ...
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0answers
17 views

Spatially inseparable data - what to do? [closed]

I'm new to machine learning and trying to solve this problem. In all tutorials, samples and so on the data is usually plotted in 2D and you can see some kind of structure which then the algorithm ...
1
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0answers
18 views

Comparing predictors based on ROC AUC and cross-validation error

I am analysing how well some continuous variables (e.g. weight, height) predict the occurrence of a given disease after surgery. I have computed the area under the curve of the receiver-operator ...
4
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1answer
62 views

Is it feasible to use k-Nearest Neighbours to identify text language?

I have seen various language identification libraries that claim to use naive Bayes classifier for text language identification, like CLD2 and language detector, but not any library that uses other ...
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8 views

Screening/Filter Method for classification problem

I have a data set with 100 variables. And the output is binary (case/control). What kind of method would be a good choice for screening variables at the beginning stage.
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17 views

Python: In which cases will random forest and SVM classifiers can produce high accuracy?

I am using Random Forest and SVM classifiers to do classification, and I have 18322 samples which are unbalanced in 9 classes (3667, 1060, 1267, 2103, 2174, 1495, 884, 1462, 4210). I use 10-fold CV ...
2
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1answer
30 views

Using Poisson process model for prediction?

Suppose some event $X$ occurs on average $10$ times per minute. The events are independent of each other. Now, if I have understood correctly, this can be modeled as a Poisson process, and I can ask ...
0
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0answers
47 views

How to check if a sample is representative or not biased?

We are studying the difference in behavior between genders on an online community. We are only interested on those users who participate in the site and whose gender could be easily inferred by other ...
2
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0answers
66 views

Combining multiple features in a classification task

This question is a little general, but I am looking for suggestions of a method. I have several images that contain images of animals and I have to characterize which animals they are, let's call them ...
2
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1answer
28 views

What is the chance level accuracy in unbalanced classification problems?

Suppose one has a balanced classification problem (50% of 0's and 50% of 1's). In such a case, the so called chance-level accuracy of classifier would be 50%. What is the chance-level accuracy if the ...
0
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1answer
22 views

How to handle unknown class during classification

Given a classification task: Training dataset "A" with labelled data of 10 classes. Training dataset "B" with unlabelled data of 11 classes. Compare to "A" , "B"contains one extra class, we can ...
1
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1answer
48 views

Feature engineering

I recently realized, that feature engineering (designing input vectors for machine-learning algorithm) is one of the most complicated tasks when applying known algorithms (for example kernel ...
0
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1answer
26 views

Naive Bayes Binary Classification with Binary Features

I have a dataset with two classes $C_0$ and $C_1$. I have around $10$ to $20$ features that take binary values (either $0$ or $1$). My dataset has around $10000$ instances, with only a hundred of ...
3
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2answers
72 views

Representative elements of a set

I'm looking for the technical name of the following problem. It sounds like a standard machine learning technique, but I'm not familiar with the field, and can't seem to find it. Let's say that we ...
0
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1answer
49 views

Which machine learning model is applicable to the following case

I want to build a model that recognizes the species based on multiple indicators. The problem is, neural networks (usually) receive vectors, and my indicators are not always easily expressed in ...
1
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1answer
32 views

Can adding an additional feature to a perceptron classifier make the results worse?

I am using perceptron to solve a classification problem. I have a limited amount of features (26) and iterate through all possible combinations of them. A combination of two features [feature_a, ...
5
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1answer
91 views

Do CART trees capture interactions among predictors?

This paper claims that in CART, because a binary split is performed on a single covariate at each step, all splits are orthogonal and therefore interactions among covariates are not considered. ...
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0answers
10 views

Variable representations for faster learning convergence

My notes on machine learning state that transforming a classification problem from 2 classes, class A = 0, and class B = 1, to class A = $(1,0)$, and class B = $(0,1)$ leads to faster convergence in ...
1
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1answer
18 views

Is there ever any reason to discretise continuous ground truth if doing classification?

Is there a case where discretising continuous response improves classification performance? For example: A response variable is in the range 0 to 99. There are 10 classes defined by the following ...
0
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2answers
51 views

Categorical as a dependent variable in regression

I am trying to use a regression model which can predict the category of an object.One object has many variables (these are used in the model as independent variables). My question is what kind of ...