# Classification

### What is Classification?

Classification is a form of supervised learning in which the objective is to classify observations into a discrete number of categories based on their input features.

### What is Multi-class Classification?

Most of the concepts of binary classification transfer over to the situation of an outcome with more than two levels, which is referred to as multi-class classification.

### What are some of the common algorithms used for classification?

Logistic regression is the most traditional classification algorithm and preserves many of the advantages in interpretation as linear regression for a continuous outcome.

### How would you address an imbalanced classification problem?

If the overall distribution of the outcome is heavily tilted towards one class compared to the other, the classification problem is considered to be imbalanced.

### How to determine threshold/decision rule for a classification model?

One of the decisions that often has to be made in a classification problem is determining what threshold to use in order to classify observations into appropriate class designations.

### What is the difference between Discriminative and Generative models?

Both discriminative and generative models have the ability to learn model parameters in a classification setting, but they are based on entirely different mechanisms and serve different purposes.

### What is Logistic Regression?

Logistic Regression is a case of Generalized Linear Model used in situations where the response variable is a binary outcome.

### What is the error / loss function in logistic regression?

Logistic regression uses a logistic loss function, where the cost for a single observation is represented by:

### What is the basic idea of Support Vector Machine (SVM) and Maximum Margin?

SVM is a classification algorithm that seeks to determine a decision boundary by maximizing the distance between points of different classes.