add lab-p13 and p13

lab-p13/README.md

lab-p13/images/README.md

lab-p13/images/barplot.png

lab-p13/images/columns.png

lab-p13/images/final.png

lab-p13/images/horizontalbarplot.png

lab-p13/images/inputs.png

lab-p13/images/piechart.png

lab-p13/images/regression.png

lab-p13/images/scatter-2.png

lab-p13/images/scatter.png

lab-p13/images/scatterplot.png

lab-p13/images/springs.png

lab-p13/images/tree-df-2.png

lab-p13/images/tree-df.png

lab-p13/practice.ipynb

p12/images/highest_ranked.PNG

p12/images/singapore_inst.PNG

p12/images/uw_madison.PNG

p13/QSranking.json