Added part 2 Data Understanding

Merge 'XHSerenaHang' into 'julie'

…eLearninginPython into XHSerenaHang

Xh serena hang

…inginPython into owen

model example is working

section 2 complted

merge Serena into julie

changed the model performance function to F1 score, also added crossing between Color and Bodytype.

section 1 preprocessing and section 2 minor edits to add F1 score

…inginPython into owen

Owen