Coin toss
A small experiment in risk.
You have $25 and 30 minutes. Bet any amount on each toss. Heads comes up 60% of the time; tails, 40%. A correct bet adds the wager to your balance. A wrong one subtracts it.
Your final balance is recorded anonymously. About the original study.
Ready?
The clock begins when you start. Toss as often as you like, until time runs out or your balance reaches zero.