# Questions tagged [naive-bayes]

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### Find conjugate and posterior distributions where data is from Normal distribution

The data $X$ is from $N(0, \cfrac{1}{\theta})$ distribution where $\theta$ is the model parameter. Find $\theta$'s bayesian conjugate prior distribution and the appropriate posterior distribution. ...
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### Likelihood calculation for Naive Bayes classifier

I am reading the Generative models for discrete data chapter in Kevin P Murphy's book(Machine Learning: A Probabilistic Perspective) Here for calculating the MLE of naive Bayes (pg no: 83) the ...
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### Bayes' Theorem in Naive Bayes Classifier

Bayes' Theorem states that: $P\left(y \mid x_1, \cdots, x_n\right)=\frac{P\left(x_1, \cdots, x_n \mid y\right) \cdot P(y)}{P\left(x_1, \cdots, x_n\right)}$ In Naive Bayes Classifier we can say the ...
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### Prove $P(B|A) = P(B)$, if $A$ and $B$ are independent [closed]

How can I show that $P(B|A) = P(B)$, given that $A$ and $B$ are independent?
1 vote
280 views

### Negative Log likelihood and Derivative of Gaussian Naive Bayes

I am trying to derive negative log likelihood of Gaussian Naive Bayes classifier and the derivatives of the parameters. So there are class labels $y \in {1, ..., k}$, and real valued vector of $d$ ...
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### Solving Bayes' Theorem

I am provided $P(A|B) = 0.980$, $P(B) = 0.0005$, $P(A'|B') = 0.987$ and I calculated $P(B') = 0.9995$. I am asked to calculate the overall probability of $P(A)$. I tried to solve it by rearranging the ...
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1 vote
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### In naive Bayesian classification, what happens if the likelihood ratio is 1?

This is a question on my assignment, I have arrived at an answer but I'm starting to second-guess myself. The grammar in the question is a bit wonky, so I'll type out the question and my ...
1 vote
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### What is the model parameters in Naive Bayes?

I just lead the Naive Bayes learning, the form is $$P(y, x_1, \dotsc, x_n) = p(y) \prod_{i=1}^n p(x_i \mid y).$$ In this lecture, it says Each factor $p(x_i \mid y)$ can be completely described by ...
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### How to compute the probability using Naive Bayes assumption?

I am struggling a bit with this question (and it's on a practice test -- not an actual test). ...
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1 vote
300 views

### Independent and Identically distributed, conditional independent and Naive bayes

I'm reading about Naive Bayes classification concept, noting that we make the conditionally independence assumption. But isn't this the general assumption that is always made dealing with machine ...
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### Bayesian Statistics: how do I calculate this probability?

Given a research with the following results: Favorite vegetable is spinach for 30% of the participants, and carrots for 70% of the participants. 40% of the participants play the drums, 50% play the ...
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### Naive Bayes classifier question [closed]

A spam filtering system has a probability of 0.95 to classify correctly a mail as spam and 0.10 probability of giving false positives. It is estimated that 0.5 % of mails are actually spam. Suppose ...
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1 vote
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### In-depth explanation of the multinomial Bayes classifier

I am new to machine learning and am trying to understand the different classifiers. I have searched the internet and books for a comprehensive explanation of the Multinomial Bayes classifier, but I ...
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### In Naive Bayes classifier how is P(sneezing,builder|flu) = P(sneezing|flu)P(builder|flu)?

Please refer to this literature: According to Naive Bayes classification algorithm: $P(sneezing,builder|flu) = P(sneezing|flu)P(builder|flu)$ where sneezing and builder are independent events. ...
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### How is the right term derived in this conditional probability statement?

Does anyone know how to get the right term? It seems like the right term is actually $P(C, x_1, x_2, \ldots, x_n)$ and not $P(C \mid x_1, x_2, \ldots, x_n)$?
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### Interpreting the results of a Naive Bayes classifier.

Using the Naive Bayes formula to classify text I have something like... $$P(Cat|Word1) = \frac{P(Word1|Cat) * P(Cat)}{P(Word1)}$$ Using a small example ... ...
493 views

### Naïve Bayes Classifier

For the Data Mining - Naïve Bayes Classifier for the case of "Numberless values for an attribute", the conditional probability is modeled with the normal distribution (see below). Probability Density ...
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### Bayesian Nets and weird probability

I have to solve the following problem: Suppose we have a bayesian net in which we have the following variables: R, PA and PR Let: P(R) = 0.1, P(PA) = 0.5, P(PR|R, PA) = 0.6, P(PR|¬R, PA) = 0.4, P(...
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### Probability with a joined condition

I want to know the probability $P(A|X,Y)$, given that I know $P(A|X)$, $P(A|Y)$, $P(A)$, $P(X)$, $P(Y)$ and given, that $X$ and $Y$ are independent. I'm also going to assume that $X$ and $Y$ are ...
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1 vote
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### Bernoulli Naive Bayes Classification

I am having trouble understanding the following text regarding Bernoulli Naive Bayes. Specifically, the author mentions that $i$ is a feature. However, what is the difference between $x_i$ and $i$?
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### How to solve conditional probability problem using bayesian algorithm

I am trying to solve An agent learning to categorise news articles in two topics, World (W) and Finance (F). Out of $100$ articles, $40$ were classified as W, and $20$ of the articles were ...
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I have an algorithm which tries to calculate some $\operatorname{Pr(X | Y_1 Y_2 \dots )}$ (where juxtaposition means event intersection, "given $Y_1$ and $Y_2$ and ... have happened".) We have some ...