# If the distribution of returns in symmetric, why not use a coin toss, small risk & high reward?

If the distribution of returns is symmetric then why not

1. use a coin toss to decide whether to buy or sell
2. Calculate the average velocity of the market (ATR - in technical analysis)
3. Place a stop loss on 0.5 ATR away from current price and take a profit 2 ATR away from the current price?

I tried it in FOREX and it doesn't seem to work. Why is this so?

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Returns do not appear to be symmetric. – SRKX Mar 30 '12 at 16:49
Your strategy seems equivalent to the following: the price $X_t$ is a standard random walk, you buy at $t=0$ and sell when it reaches -1/2 or 2 (whichever comes first). In this case, the expected profit is zero. – Vincent Zoonekynd Mar 31 '12 at 0:27