K-Nearest Neighbors (KNN) Technique

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Questions and Answers

What is the primary advantage of the K-Nearest Neighbors algorithm?

Ability to handle high-dimensional data
Fast computation and low memory usage
Robustness to outliers and noisy data
Conceptually simple and easy to understand (correct)

What is the main goal of Support Vector Machines?

To maximize the margin between the support vectors (correct)
To identify the most important features
To reduce the dimensionality of the data
To minimize the error between predicted and actual values

What is a common limitation of the K-Nearest Neighbors algorithm?

It is robust to noisy and irrelevant features
It is sensitive to the choice of distance metric (correct)
It requires a large amount of training data
It can handle high-dimensional data with ease

What is the role of support vectors in Support Vector Machines?

To constrain the width of the margin (C) Signup and view all the answers

Which of the following is NOT an advantage of the K-Nearest Neighbors algorithm?

Robust to noisy and irrelevant features (B) Signup and view all the answers

What is the primary difference between Support Vector Machines and K-Nearest Neighbors?

SVMs maximize the margin, while KNN finds the nearest neighbors (C) Signup and view all the answers

What is a common application of Support Vector Machines?

Image recognition and object detection (B) Signup and view all the answers

What is a disadvantage of the K-Nearest Neighbors algorithm?

It can be computationally expensive for large datasets (C) Signup and view all the answers

What type of classification algorithm is a Decision Tree?

Non-linear Model (B) Signup and view all the answers

Which of the following is an example of a Multi-class Classifier?

Classification of types of music (C) Signup and view all the answers

What type of Logistic Regression has only two possible outcomes?

Binomial (D) Signup and view all the answers

Which of the following is NOT a type of Linear Model?

K-Nearest Neighbours (D) Signup and view all the answers

What is the key characteristic of a Binary Classifier?

Exactly two possible outcomes (D) Signup and view all the answers

Which of the following is an example of a Non-linear Model?

K-Nearest Neighbours (C) Signup and view all the answers

What is the purpose of a classifier in a classification algorithm?

To implement the classification on a dataset (D) Signup and view all the answers

Which of the following classification algorithms is NOT a Non-linear Model?

Support Vector Machines (D) Signup and view all the answers

What is the primary function of a hyperplane in SVM?

To split the data into two parts for classification (C) Signup and view all the answers

What is the advantage of SVM in terms of the number of variables and sample size?

It is robust to very large number of variables and small samples (A) Signup and view all the answers

What is the purpose of the Kernel function in SVM?

To transform non-linearly separable data into a higher dimension (B) Signup and view all the answers

What is the main advantage of Naïve Bayes algorithm?

It can make quick predictions with high-dimensional training datasets (D) Signup and view all the answers

What is the main application of Naïve Bayes algorithm?

Text classification (C) Signup and view all the answers

What is the primary goal of classification algorithms?

To classify data into predefined categories (D) Signup and view all the answers

What is the main difference between classification and regression?

Classification is used for categorical variables, while regression is used for continuous variables (C) Signup and view all the answers

What is the main advantage of SVM over other classification algorithms?

It can handle non-linearly separable data (A) Signup and view all the answers

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Study Notes

K-Nearest Neighbors (KNN)

KNN is a simple classification technique that assigns the majority class label among the k-nearest neighbors to a new data point
Advantages: conceptually simple, easy to understand and explain, very flexible decision boundaries, and not much learning required
Disadvantages: hard to find a good distance measure, irrelevant features and noise can be detrimental, can't handle more than a few dozen attributes, and high computational cost

Support Vector Machine (SVM)

SVM is a geometric model that views input data as vectors in an n-dimensional space and constructs a separating hyperplane that maximizes the margin between two data sets
A good separation is achieved by the hyperplane that has the largest distance to the neighboring data points of both classes
Maximizes the margin around the separating hyperplane, and the decision function is fully specified by a subset of training samples, the support vectors
Can be used for both classification and regression tasks
Advantages: robust to a large number of variables and small samples, can learn simple and complex models, employs sophisticated mathematical principles to avoid overfitting, and effective in cases of limited data

Naïve Bayes Classifier

Naïve Bayes is a simple and effective classification algorithm that is mainly used in text classification with high-dimensional training datasets
Examples of Naïve Bayes Algorithm: spam filtration, sentimental analysis, and classifying articles

Classification Algorithms

Classification algorithms are used when the output variable is categorical
Popular classification algorithms: Logistic Regression, Decision Trees, Naïve Bayes, Support Vector Machines, KNN, and Random Forest
Classification algorithms can be divided into two categories: Linear Models (Logistic Regression, Support Vector Machines) and Non-linear Models (K-Nearest Neighbours, Decision Tree, Naïve Bayes, Random Forest)