What is Machine Learning?

• Answer: Machine Learning is a subset of artificial intelligence that enables systems to learn and make predictions or decisions based on data without explicit programming.

Explain the difference between supervised and unsupervised learning.

• Answer: In supervised learning, the algorithm is trained on a labeled dataset, while in unsupervised learning, the algorithm works on an unlabeled dataset without predefined outcomes.

What is the bias-variance tradeoff?

• Answer: The bias-variance tradeoff is a key concept in machine learning that balances the error due to bias (underfitting) and variance (overfitting) to find an optimal model complexity.

Describe the curse of dimensionality.

• Answer: The curse of dimensionality refers to the challenges and increased complexity associated with high-dimensional data, where distances between points become less meaningful and models may struggle to generalize.

Explain feature engineering.

• Answer: Feature engineering involves transforming raw data into a format that enhances the performance of machine learning algorithms by highlighting important patterns and relationships.

What is regularization, and why is it important?

• Answer: Regularization is a technique used to prevent overfitting in machine learning models by adding a penalty term to the cost function, discouraging overly complex models.

Differentiate between classification and regression.

• Answer: Classification involves predicting discrete categories, while regression predicts continuous values.

What are precision and recall?

• Answer: Precision is the ratio of correctly predicted positive observations to the total predicted positives, while recall is the ratio of correctly predicted positive observations to all actual positives.

Explain the ROC curve.

• Answer: The Receiver Operating Characteristic (ROC) curve illustrates the trade-off between true positive rate and false positive rate across different threshold values.

What is cross-validation?

• Answer: Cross-validation is a technique used to assess a model’s performance by partitioning the data into subsets, training the model on some, and testing on the others to ensure robustness.

What is the difference between bagging and boosting?

• Answer: Bagging (Bootstrap Aggregating) involves training multiple models independently and combining their predictions, while boosting focuses on training models sequentially, with each trying to correct the errors of its predecessor.

Explain the concept of a decision tree.

• Answer: A decision tree is a flowchart-like structure where each internal node represents a decision based on a feature, each branch represents an outcome, and each leaf node represents a class label.

What is the K-nearest neighbors algorithm?

• Answer: K-nearest neighbors is a simple algorithm that classifies a new data point based on the majority class of its k-nearest neighbors in the feature space.

What is the purpose of the term “dropout” in neural networks?

• Answer: Dropout is a regularization technique used in neural networks to randomly deactivate some neurons during training, preventing overfitting.

Explain the concept of a confusion matrix.

• Answer: A confusion matrix is a table that summarizes the performance of a classification algorithm, showing the counts of true positive, true negative, false positive, and false negative predictions.

What is gradient descent?

• Answer: Gradient descent is an optimization algorithm used to minimize the cost function by iteratively adjusting model parameters in the direction of the steepest decrease in the gradient.

Describe the difference between L1 and L2 regularization.

• Answer: L1 regularization adds the absolute values of the coefficients to the cost function, encouraging sparsity, while L2 regularization adds the squared values of the coefficients, preventing large weights.

What is the purpose of the activation function in a neural network?

• Answer: The activation function introduces non-linearity to the neural network, allowing it to learn complex patterns and relationships in the data.

What is the difference between overfitting and underfitting?

• Answer: Overfitting occurs when a model performs well on training data but poorly on new, unseen data, while underfitting happens when a model is too simple to capture the underlying patterns in the training data.

What is the ROC-AUC score?

• Answer: The ROC-AUC (Receiver Operating Characteristic – Area Under the Curve) score is a metric that quantifies the area under the ROC curve, providing a single value to assess the performance of a classification model.

Explain the term “hyperparameter tuning.”

• Answer: Hyperparameter tuning involves optimizing the parameters that are not learned by the model itself, such as learning rates or the number of hidden layers, to enhance the model’s performance.

What is a support vector machine (SVM)?

• Answer: SVM is a supervised learning algorithm used for classification and regression tasks. It aims to find the hyperplane that best separates data points of different classes.

Describe the concept of transfer learning.

• Answer: Transfer learning involves using knowledge gained while solving one problem to help solve a different but related problem, often by leveraging pre-trained models on large datasets.

How does a Recurrent Neural Network (RNN) differ from a Feedforward Neural Network?

• Answer: Unlike a Feedforward Neural Network, an RNN has connections that form a directed cycle, allowing it to capture information about previous states, making it suitable for sequence data.

Explain the term “ensemble learning.”

• Answer: Ensemble learning combines the predictions of multiple models to improve overall performance and generalization, with popular methods including bagging (e.g., Random Forests) and boosting (e.g., AdaBoost, Gradient Boosting).