Ask the Slot Expert: Sample size works both ways

A few months ago I wrote about how the relatively small bankroll I had been allocating for a casino visit led me to have a disappointing number of sessions in which I ran out of money before I had played the number of hands I wanted to play to keep on pace with requalifying for an upper tier in the slot club.

Even though the long-term payback on NSU Deuces is 99.7%, I was experiencing paybacks in the high 80s and low 90s in some sessions. I didn't allocate enough money to see me through the cold spells. As a result, my sample size was so small that my session paybacks fell into a very wide range.

The larger your sample, the closer the value you're measuring will tend to be to that of the population you are sampling. The more hands or spins you play, the closer your payback will tend to be to the long-term payback of the machine you are playing.

A few weeks ago, I wrote about my good fortune playing on my birthday. A kiosk gave me a birthday wish and a video poker machine gave me three sets of deuces in under 50 hands. Needless to say, that was a happy birthday.

I was anxious to see how much of the money I won from those deuces I could hold on to. For a while my credit meter bounced up and down around the $3000 mark, then Lady Fortune got tired of looking after me and left to find someone else to smile on. I bid adieu to the machine after it took back half a deuces payoff.

It occurred to me that sample size works both ways. Over the summer, I was considering how increasing my session bankroll would let me play more hands per session and my actual payback would tend to be closer to 99.7%. As I watched my credit meter slowly decrease, I realized that the 2000+% payback I had experienced so far would also tend to fall down to 99.7%.

More play moves you away from the short term and closer to the long term. More play tends to bring you closer to the long-term payback.

I have to say "tend to" because we have to acknowledge randomness. You could have a 200-hand session that was breakeven and a 400-hand session that had a royal and a payback that was well above breakeven. More play after I hit my first set of deuces didn't lower the payback I was experiencing, it increased it as I hit more sets of deuces.

There's only one way to avoid approaching your game's long-term payback with more play: Stop playing.

That reminds me of something that happened when my brother was visiting Las Vegas and I was playing some NSU for him with his $20. I hit a straight flush and he was up a few dollars.

"You would stop now, right?" he asked me.

"Well...."

If you would like to see more non-smoking areas on slot floors in Las Vegas, please sign my petition on change.org.