role of dendrograms in agglomerative hierarchical clustering machine learning algorithms knn algorithm knn algorithm finding nearest neighbors introduction working of knn algorithm implementation in python knn as classifier knn as regressor pros and cons of knn applications of knn machine learning algorithms performance metrics performance metrics for classification problems performance metrics for regression problems machine learning with pipelines automatic workflows introduction challenges accompanying ml pipelines modelling ml pipeline and data preparation modelling ml pipeline and feature extraction machine learning improving performance of ml models performance improvement with ensembles ensemble learning methods bagging ensemble algorithms boosting ensemble algorithms voting ensemble algorithms machine learning improving performance of ml model (contd performance improvement with algorithm tuning performance improvement with algorithm tuning viii