People have more vivid memories of the colorful, Super Bowl Shuffling 1985 Bears (also 15-1 with a second-best all time standard deviation of 2.10), because that club was a one-year wonder that never got back to a Super Bowl.

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The MSCI Emerging Markets Index is only about a half of a standard deviation from its mean over the same time frame.

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One common yardstick of volatility is standard deviation, which uses annualized monthly returns over time as a baseline.

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This is only feasible if the prior deviation from this parity is relatively small, and the time since that parity was used relatively short.

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My sense, though, is that much of the success of high frequency trading operations might be along the lines of what the 21 players discovered years ago after taking the time to work through the basic math and apply the simple stuff such as standard deviation.

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One standard deviation is defined as the price band a security trades in 68% of the time.

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