Supervised Learning
Supervised learning involves training a model on a labeled dataset. Labeled data means the input data is paired with the correct output. The goal is for the model to learn the mapping or relationship between inputs and outputs so that it can make predictions or classify new, unseen data accurately. There are two main types of supervised learning:
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Classification: This involves predicting a categorical label. For instance, determining whether an email is spam or not spam based on certain features (like words used, sender, etc.). Algorithms like Support Vector Machines (SVM), Decision Trees, and Neural Networks are used for classification.
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Regression: Involves predicting a continuous value. For instance, predicting the price of a house based on its features like area, number of bedrooms, etc. Algorithms like Linear Regression, Random Forest, and Gradient Boosting are used for regression tasks.
Unsupervised Learning
Unsupervised learning involves training a model on an unlabeled dataset. Here, the algorithm tries to find hidden patterns or intrinsic structures in the data without any explicit supervision. The aim is to explore the data, understand its structure, and extract meaningful insights. Common types of unsupervised learning include:
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Clustering: Grouping similar data points together based on certain features or similarities. For example, clustering customer segments based on their purchasing behavior using algorithms like K-Means or Hierarchical Clustering.
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Dimensionality Reduction: Reducing the number of features while retaining essential information. Principal Component Analysis (PCA) and t-Distributed Stochastic Neighbor Embedding (t-SNE) are used to visualize high-dimensional data in a lower-dimensional space.
When to Use Each
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Supervised Learning is used when you have labeled data and want to predict or classify future instances based on that labeled data. For instance, if you have historical data on customer purchases and want to predict future purchases, supervised learning is suitable.
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Unsupervised Learning is used when you don't have labeled data or when you want to explore and understand the underlying structure of the data. For example, in anomaly detection or finding hidden patterns in large datasets.
Sometimes, a combination of both types of learning, known as semi-supervised learning, can be employed when you have a small amount of labeled data and a large amount of unlabeled data, allowing models to benefit from both sources of information.
