# multi armed Bandit Problem

I am studying machine learning, I remember what are distributions, mean, median mode, from my university statistics studies, but the author, says that given five slot machines with these distributions, the number 5 is good, as it is left skewed and has as consequence favorable mean, mode and median. Also he states that also the 4th should be good. Of course for good he means the probabilities I would have to win money from them. Why 5 distribution is best and why the 4th is also acceptable.

With common sense I would say that bigger is the area "expecially on top" better the distribution is. Which basic concept I am missing?

EDIT: the author of the course says:

"Each one of the machines has a distribution out of which the machine picks results, randoms pulling the arm of the machine. The one on the right is the best machine because has the best outcome as the highest mean, median and mode."

In the comments is written: Then in the comments of the course I tooks people say: the reason you are chosing the orange(yellowish) one is these graphs are Probability Distributions and therefore by definition they range between 0 and 1

And the reason we want ORANGE is because the MEAN of this probability distribution is LEANING to the RIGHT and hence a higher number in the range of 0 to 1

here 0 is 0% and 1 is 100% in terms of probability distributions.

And the tutor said, yes you are right.

• Erm... don't you mean 'the more mass the probability distribution puts to the right, the better'? Because money is noted on the x-Axis from left (little money) to the right (much money) and the height just means how 'spiky' the distribution is, i.e. how uncertain we are that we actually get the high amount of money... Commented Feb 2, 2018 at 13:27
• Please see the EDIT. (Ps. I cannot upvote you tbecause you appear as comment and not as a reply.If you like you could put a small graph so that you will have a proper answer) Commented Feb 2, 2018 at 13:36