Hi Can you please let me know the difference b/w different models in Data science. below are my questions: 1)what is the difference b/w gradient boosting regressors and linear regression ,if gradient boosting regressors gives more accuracy why you did not cover it in this course..? 2)what is the difference b/w random forest and KNN ..? my understanding: According to my understanding in Random forest also variables does not follow any pattern(not like in liner regression which follows normal distribution) just as KNN then why random forest called parametric test while KNN called as non parametric test 3) Also Please let me know what model i should use if i have categorical data as variables ..? Regards, Surya.