Feature Engineering and Selection Questions

Covers the end to end process of transforming raw data into predictive and stable model inputs and choosing the most useful subset of those inputs. Topics include generating features from domain signals and timestamps, numerical transformations such as scaling binning and logarithmic transforms, categorical encodings including one hot and target encoding, creation of interaction and polynomial features, construction of dense feature vectors for model consumption, handling missing values and outliers, and strategies for class imbalance. Also includes feature selection and dimensionality reduction methods such as filter techniques statistical tests wrapper methods embedded model based selection mutual information analysis and tree based importance measures. Emphasis is placed on avoiding data leakage validating feature stability over time interpreting feature contributions and documenting rationale for feature creation or removal. For senior roles include designing feature engineering best practices mentoring others and considering feature impact on model interpretability and business metrics.