Knowee
Questions
Features
Study Tools

Consider a binary classification problem with two classes, A and B with prior probability P(A)=0.6𝑃(𝐴)=0.6 and P(B)=0.4𝑃(𝐵)=0.4 .Let X be a single binary feature that can take values 00 or 11. Given: P(X=1|A)=0.8𝑃(𝑋=1|𝐴)=0.8 and P(X=0|B)=0.7𝑃(𝑋=0|𝐵)=0.7. Determine which class the classifier will classify when X=1𝑋=1.

Question

Consider a binary classification problem with two classes, A and B with prior probability P(A)=0.6𝑃(𝐴)=0.6 and P(B)=0.4𝑃(𝐵)=0.4 .Let X be a single binary feature that can take values 00 or 11. Given: P(X=1|A)=0.8𝑃(𝑋=1|𝐴)=0.8 and P(X=0|B)=0.7𝑃(𝑋=0|𝐵)=0.7. Determine which class the classifier will classify when X=1𝑋=1.

🧐 Not the exact question you are looking for?Go ask a question

Solution 1

To determine which class the classifier will classify when X=1, we need to calculate the posterior probabilities P(A|X=1) and P(B|X=1) and compare them. The class with the higher posterior probability will be the predicted class.

  1. Calculate P(X=1), the total probability that X=1:

P(X=1) = P(X=1|A)P(A) + P(X=1|B)P(B)

We know P(X=1|A) = 0.8 and P(A) = 0.6. We don't know P(X=1|B), but we know P(X=0|B) = 0.7, so P(X=1|

This problem has been solved

Solution 2

To determine which class the classifier will classify when X=1, we need to calculate the posterior probabilities P(A|X=1) and P(B|X=1) and compare them. The class with the higher posterior probability will be the predicted class.

The posterior probability can be calculated using Bayes' theorem:

P(A|X=1) = P(X=1|A) * P(A) / P(X=1) P(B|X=1) = P(X=1|B) * P(B) / P(X=1)

We know that P(X=1|A) = 0.8 and P(A) = 0.6. However, we don't know P(X=1) and P(X=1|B).

We can calculate P(X=1) using the law of total probability:

P(X=1) = P(X=1|A) * P(A) + P(X=1|B) * P(B)

But we don't know P(X=1|B). We only know that P(X=0|B) = 0.7. Since X is a binary feature, it can only take values 0 or 1. Therefore, P(X=1|B) = 1 - P(X=0|B) = 1 - 0.7 = 0.3.

Now we can calculate P(X=1):

P(X=1) = 0.8 * 0.6 + 0.3 * 0.4 = 0.48 + 0.12 = 0.6

Now we can calculate the posterior probabilities:

P(A|X=1) = 0.8 * 0.6 / 0.6 = 0.8 P(B|X=1) = 0.3 * 0.4 / 0.6 = 0.2

Since P(A|X=1) > P(B|X=1), the classifier will classify X=1 as class A.

This problem has been solved

Similar Questions

Consider a classification problem where the input space consists of 10 binary features (X₁, X₂, ..., X₁₀) and the output space consists of two classes (0 and 1). A dataset of 100 training examples is given, with the following feature values and corresponding class labels:Example 1: (0, 1, 1, 0, 1, 0, 1, 0, 0, 1) → Class: 0Example 2: (1, 0, 0, 1, 1, 1, 0, 1, 0, 1) → Class: 1Example 3: (1, 1, 1, 0, 0, 1, 0, 0, 1, 0) → Class: 1Example 100: (0, 0, 1, 0, 1, 0, 1, 1, 0, 1) → Class: 0You are tasked with building a supervised learning model using logistic regression. Each feature Xi is binary and can take values 0 or 1. You decide to use one-hot encoding to represent the input features. After applying one-hot encoding, how many features will the dataset have for training the logistic regression model?a)19b)20c)10d)18

Probability of Error: For performing classification, Bayesian selection criteria minimizes theprobability of misclassification. When classifying an input x, the Bayesian selection criteriawill assign x to its most probable class. Given a set of L classes (c1, c2, ..., cL), the probability ofx belonging to class ci is given as P (ci|x). The maximum conditional probability is describedas: P (ci∗ |x) = argmaxiP (ci|x). From this, derive the Bayesian conditional probability ofmisclassification, P ∗(e|x), for a given input x and express its average over the prior distributionof x.

k-NN: This problem derives a performance bound on the 1-NN classifier. Consider the 1-NN binaryclassifier on a two-dimensional space. For an input x and its nearest neighbor xn in the trainingdata, the conditional probabilities of belonging to classes c1 and c2 are as follows:◦ p(c1|x) : probability that x belongs to c1◦ p(c2|x) : probability that x belongs to c2◦ p(c1|xn) : probability that xn belongs to c1◦ p(c2|xn) : probability that xn belongs to c2Knowing that p(c1|x) + p(c2|x) = 1 and p(c1|xn) + p(c2|xn) = 1,(a) Express the conditional probability of misclassification error, e, for x, P (e|x, xn), in terms ofthe probabilities provided above.

We are given that P(A | B) = 0.6 and P(A) = 0.9. Since P(A | B) ≠ P(A), the occurrence of event B changes the probability that event A will occur. This implies that A and B are events.

How does the Naive Bayes classifier calculate the probability of a data point belonging to a particular class?Select one:a.By using the least squares methodb.By using the gradient descent algorithmc.By using the maximum likelihood estimationd.By using the Bayes theorem

1/1

Upgrade your grade with Knowee

Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.