Alrighty, bored at work so I just worked out a probability table of "roll twice, take the higher result". For a d4, I got that the average increases by .75, bringing it to a nice round 3.25 average. For a d20, I got an average increase by ~3.25, giving us an average of about 13.75.

Then I remembered I've never taken a statistics class and probably got this entirely wrong.

Anyone have any real math on "roll twice, take the higher" on a d20?

Then I remembered I've never taken a statistics class and probably got this entirely wrong.

Anyone have any real math on "roll twice, take the higher" on a d20?