A naive Bayes classifier is a simple probabilistic classifier based on applying Bayes' theorem with strong independence assumptions. A more descriptive term for the underlying probability model would be "independent feature model".

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Why naive bayes classifier cannot perform correctly on 1 conditional probability?

I use e1071 package for naive bayes classification. My dataset is having 2 condition/feature (FF1 and FF2) to predict a class of signal (ELO or FP). When I used the following line of code: ...
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14 views

Why are Bayesian classifiers “robust to noise”?

In many different settings I've read that Bayesian classifiers like Naïve Bayes and Bayesian Networks are more robust to noise in the input data than other classifiers. I'm wondering what the evidence ...
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39 views

Naive Bayes: Continuous and Categorical Predictors

It's my understanding that most types of common classifiers (Support Vector Machine, for example) can take a mixture of categorical and continuous predictors. However, this doesn't seem to be true ...
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18 views

Probability of class membership given univariate normal distribution

Assuming a class is well described with a normal distribution of u and s, is it reasonable to calculate the probability of membership as: $Pr(x)=Pr(|x-u|)=2.0*\text{cdf}(|x-u|,s)$? I've briefly ...
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16 views

Obtaining and sampling from the posterior predictive of a naive Bayes classifier

I have trained a naive Bayes classifier with on a dataset with a dichotomous outcome and multinomial attributes (predictors). I managed to get a Maximum a posteriori (MAP) estimate which is good ...
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11 views

How to cross validate with optimal sample size selection?

My problem is as follows: I got a training set composed of texts, where 10% of observations are 1, and 90% are 0. To make it simpler, lets say that 1000 is 1, and 9000 is 0. I implement Naive Bayes ...
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1answer
81 views

Machine learning techniques for spam detection, and in general for text classification

I am going to configure a system for spam detection. What I have is a dataset of labeled (spam/not-spam) strings containing, mostly, sentences. I have a background in machine learning techniques, but ...
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11 views

Naive Bayes Classifier - measure accuracy after training

I have built a prototype Naïve Bayes Classifier in an Excel spreadsheet. My data is a transaction (an order) with 13 parameters. This translates directly to a feature vector of (feature_1, feature_2, ...
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41 views

Exploratory Analysis - finding the most important factor

I have a dataset of 113 variables. In exploratory analysis the first thing I want to know is what are the most important factors on a single variable (revenue). I learned that naive Bayes would ...
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1answer
33 views

How can I convert variable distribution parameters into training data for Naive Bayes classifier?

I am trying build a Naive Bayes classifier from data pulled from scientific papers. I want to use the reported variable distribution parameters to approximate a dataset which I can use to train the ...
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1answer
44 views

Simple question about multivariate/multiclass classification

From this link Text Classification using Naive Bayes, there are two models described for classification, Naive and Bernoulli. My question is if i want to make this classifiers for multiclass ...
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1answer
147 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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1answer
107 views

Why does nobody use the Bayesian multinomial Naive Bayes classifier?

So in (unsupervised) text modeling, Latent Dirichlet Allocation (LDA) is a Bayesian version of Probabilistic Latent Semantic Analysis (PLSA). Essentially, LDA = PLSA + Dirichlet prior over its ...
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3answers
186 views

Naive Bayesian Algorithm in R/SAS for categorical input variables?

Could anyone please let me know how to implement Naive Bayesian Algorithm in R or SAS?I have got a training dataset with all the categorical predictors and target variable(3 levels).I got to build a ...
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1answer
195 views

Logistic Regression\SVM implementation in Mahout

I am currently working on sentimental analysis of twitter data for one of telecom company data.I am loading the data into HDFS and using Mahout's Naive Bayes Classifier for predicting the sentiments ...
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72 views

Sentimental Analysis using Naive Bayes

I am working on problem solution where I am collecting social feeds from twitter and Facebook for a product X . I am labeling these posts,comments or tweets using five labels ...
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134 views

multiple distribution bayesian classification

There is already Gaussian Naive Bayesian, but can other distributions be used to fit the features' value to calculate the likelihood? For the data set I have, some feature are more like inverse ...
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33 views

Correct way to combine bigrams and unigrams in naive bayes classifier?

I'm writing naive bayes classifier for spam detection. I'd like it to recognize difference between "Paris Hilton" and "Hilton Paris", so I'm using bigrams in addition to unigrams. Currently I throw ...
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25 views

How to choose training sets for textual data?

I have textual data scraped from a classified ads site and I'm interested in classifying the posts into two categories: "X" and "not X". I'm stuck with coming up with a good training set and feature ...
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2answers
31 views

Evaluating unbiased errors on the Test set when cross validation scores are close

I trained a few different models, (Perceptron, Stochastic Gradient Descent and Naive Bayes), each with different parameters. I then scored their accuracy on a cross validation set. The scores on the ...
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1answer
46 views

Bayesian Classification evaluation

I am trying to implement Bayesian Classification on the data set as follows: "Problem: classify whether a given person is a male or a female based on the measured features. The features include ...
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100 views

Naive Bayes model [duplicate]

i am trying to implement the naive bayes algorithm in java. But i have a few confusions on the naive bayes model. What is the model of naive bayes? Is it a table ?how we can make prediction from the ...
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128 views

Predicting Naive Bayes model in R on a test data with a single record

I built a naivebayes model using the Housevotes84 data(discrete data) in mlbench package- model <- naiveBayes(Class~., data=HouseVotes84) I took one record ...
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58 views

In what conditions does naive Bayes classifier perform poorly?

When does naive Bayes perform poorly? Can you think of any specific examples of problems in which it wouldn't work? We can ignore not having seen given data points before as that can be corrected by ...
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148 views

Machine Learning to Predict Class Probabilities

I am looking for classifiers that output probabilties that examples belong to one of two classes. I know of logistic regression and naive Bayes, but can you tell me of others that work in a similar ...
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54 views

construct naive bayes classifier using defined characteristic

I found a paper about using naive bayes classification for identifying interested user. In that paper, they use some characteristic to define whether user is interested or not. However, they do not ...
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228 views

Prediction using Naive Bayes of klaR package fails

I am trying to replicate a example that I found in Tom Mitchell's book Machine Learning (1997), using R. It is a example from chapter 6. There are 14 training examples (shown below) of the target ...
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104 views

Why Bayes Rule in Naive Bayes compared to simple P(class|features)

I would like to improve on my recommendation system. Imagine I have training data of $M=7,000,000$ samples. Each training sample contains a variable number of words in the body, and a variable amount ...
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1answer
149 views

What is the meaning of this formula in R?

I have rows of data with columns age, sex, education and ...
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93 views

Maximizing incomplete likelihood

Given the conditional distribution $p(x|y)$ and the prior of the hidden variables $p(y|\theta)$ with unknown hyper-parameter $\theta$. Now we have observed i.i.d. samples of $x$. Besides the Bayes ...
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53 views

Bayesian, Fisher method: model very simple data to get discriminants

I've just implemented a naive Bayesian classifier and found out about the Fisher method (Linear discriminant analysis and Bayes rule) while looking for ways to improve it. I'm very new to this field. ...
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2answers
286 views

Why does Naive Bayes outperform Support Vector Machines?

I have a dataset composed of about 36000 attributes and 550 samples, the dataset is generated from text communication between people in some chatrooms. The questions is when I try to classify these ...
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49 views

Naive Bayes with invalid independence assumption

I'm trying to understand the effects of adding non-conditionally independent features to a naive Bayes classifier. Let's say I have the features vector $X = [x_1,x_2,x_3,x_4]$ and that for each value ...
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55 views

Bayes Theorem for Continuous Value Attributes

I need any solved example/data set which explain how to apply Bayes Theorem for continuous value attributes. I read the book (Machine Learning by Tom Mitchell) and found this equation. But I need some ...
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3answers
105 views

Graphical Probabilistic Representation of Naive Bayes

Given the Naive Bayes graphical representation below, I want to calculate $P(X|Y_1,Y_2)$. Are the calculations below correct? The factored joint distribution regarding the system is: ...
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105 views

Can a Naive Bayes classificator “learn” variables which are not in the training set?

Theory I have three data sets, let's call them A, B and C. These data sets contain the following variables: ...
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1answer
87 views

Unsupervised Bayesian naive Bayes

I'm reading a paper Gibbs sampling for the uninitiated. In this paper, the authors try to use Gibbs sampling for a bayesian naive bayes model. They formalize the model as a graphical model in page 8. ...
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89 views

Sentiment Analysis with respect to subject

I'm familiar with the bag of words/Naive bayes sentiment analysis for text (e.g. http://streamhacker.com/2010/05/10/text-classification-sentiment-analysis-naive-bayes-classifier/) I was curious to ...
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1answer
87 views

Naive Bayesian class probability greater than one

I have a problem with a simple Naive Bayes calculation. Given that I have an inbox, with the following characteristics: The mailbox contains 100 emails 50 emails contain the word “money”. 30 emails ...
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2answers
67 views

Equal number of training instances of each classification label?

I am using Naive Bayes to perform binary classification. In my training set, the two class labels occur with probability Pr(label A) = 0.95 and Pr(label B) = 0.05. Should I prune the training set so ...
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2answers
235 views

Incorporating the effect of sample size in maximum likelihood estimation

I have two sample sets that consist of independent trials of a binomial variable X = {X0, X1}. For the remainder, I denote the probabilities as ...
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1answer
134 views

Naive Bayes classifier gives a probability greater than 1

I'm trying to understand an example regarding how to use a Naive Bayes classifier in spam filtering based on this link. The article picks two "bad" words that they figure are in spam a lot and then ...
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127 views

Need help with some surprising classifications by naiveBayes

We are trying to do a POC on using NaiveBayes to classify an establishment by the category. We loaded the following training set in R. ...
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71 views

Degenerate cases when using naive bayes to infer a beta distributed variable

I'm trying to predict the distribution of a variable that I expect to be beta distributed, conditional on some associated text. I've measured the beta distributions conditioned on each term ...
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1answer
75 views

Trouble reading multinomial naive bayes notation

$C_{MAP}$: most likely class (i.e., "maximum a posteriori") $C_{NB}$: Naive Bayes x: document d is represented as $x_n$ ...
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2answers
139 views

Logistic Regression/Naive Bayes with highly correlated data

Background: We work with data from sports event, more accurately with data about the spectators of sports events: how many people are being violent, what kind of event is this, etc. We have quite a ...
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2answers
92 views

Why is naive Bayes a linear model?

People always said that naive Bayes is a linear model. I am not able to understand why, so can anybody explain?
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1answer
109 views

When to use ridge estimator / naive Bayes

I used the Logistic function in weka, to predict a binary class. I have used SimpleLogistic before, but Logistic also seem to give me good results. I did want to clarify if I understand some things ...
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483 views

Naive Bayes on continuous variables

Please allow me to ask a basic question. I understand the mechanics of Naive Bayes for discrete variables, and can redo the calculations "by hand". (code of HouseVotes84 all the way per below). ...
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135 views

Understanding Naive and Multivariate Gaussian Classifier

Thank you for checking this question out. I am trying to understand how to use the multivariate gaussian classifier. To introduce you better to my problem, I will show how currently I classify data. ...