Create three new columns: P(Ln-1), P(Ln-1|RESULT), and P(Ln). Leave the columns below them empty for now. Just temporarily, set up column P(Ln) so that it build on the previous column P(Ln-1) with an increase of 0.1. (This pretends that the student always gets 10% better each time, even going over 100%, which is clearly wrong...; we'll fix it later.)



What should the formula be for column P(Ln-1)? If you're not sure which of these is right, try them out.

A. df3.loc[df3["Student"] != df3["Student"].shift(-1), "P(Ln-1)"] = L0
B. df3.loc[df3["Student"] != df3["Student"].shift(), "P(Ln-1)"] = L0
C. df3.loc[df3["Student"] != df3["Student"].shift(1), "P(Ln-1)"] = df3["Student"].shift(1)
D. df3.loc[df3["Student"] == df3["Student"].shift(), "P(Ln-1)"] = L0
E. df3.loc[df3["Student"] == df3["Student"].shift(-1), "P(Ln-1)"] = df3["P(Ln)"].shift()
F. df3.loc[df3["Student"] == df3["Student"].shift(1), "P(Ln-1)"] = df3["P(Ln)"].shift()

Use Comma to seperate multiple options, such as A,B