FREE Data Science MCQ Question and Answers Flashcards
6 cards from real Data Science practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 FREE Data Science MCQ Question and Answers flashcards as text
Which technique is used to reduce the number of features in a dataset while preserving most of the variance?
Answer: Principal Component Analysis
PCA reduces dimensionality by transforming features into principal components that capture the maximum variance in the data.
What does the term 'overfitting' refer to in a machine learning model?
Answer: The model performs well on training data but poorly on unseen data
Overfitting occurs when a model learns noise in the training data, resulting in poor generalization to new data.
In a confusion matrix, what does the 'recall' metric measure?
Answer: The proportion of actual positives correctly identified
Recall measures the ability of a model to find all relevant positive instances out of the total actual positives.
Which of the following is a supervised learning algorithm?
Answer: Random Forest
Random Forest is a supervised ensemble method that uses labeled data to build multiple decision trees for classification or regression.
What is the purpose of cross-validation in model evaluation?
Answer: To estimate how well a model generalizes to independent datasets
Cross-validation splits data into multiple folds to test model performance across different subsets, providing a robust estimate of generalization.
Which Python library is primarily used for creating dataframes and performing data manipulation?
Answer: Pandas
Pandas provides the DataFrame structure and a rich set of functions for data cleaning, transformation, and analysis.