2 SIGMA SPREAD TRADING
Thats interesting because I have been diddling with it. To me it looks more like it would be covering all around the mean average. ( both sides ) The 1 sigma numbers would be scattered, spread across the average is the way I am seeing it in practice here on my work.
To give you an example, I have been allocating 3 strikes, or 15 points each side of the OEX and legging into the spreads when I get movement from Mondays, trading a weekly bar, when the index moves outward from the starting average at OPEN on Monday. Doing this I am assuming I have a 1 sigma deviation with a little more than my three strikes. When I do the simple calculation from the formula INDEX VALUE x VOLATILITY X the number of days divided by 365 left to expiration. I am getting 33 points, or 6.5 strikes, for last FRIDAY. ( 1 day to expiration )
Now if 1 SIGMA is on EACH side as you say, that becomes impossible to work, ( at 66 points wide ) because there are no premiums that far away from the average starting point. If the 1 SIGMA is the spread covering ALL of the average on both sides and I saw a pictoral diagram that looked exactly that way, but no written explanation ( sort of random dots around the average ) then I split my number and it becomes workable for me as a strategy. It is still far out but possible to get close to the outside partially to put on a safe spread. The probability of a 1 SIGMA system is 68 %. Which kind of fits in with my spreads getting almost done in last month twice. The index ran out over 15 points, or 3 strikes.
They say a 2 SIGMA deviation though is a 100% earner, but in that case it is not possible to find any trade premiums that far away, even legging in.. I don't know how to calculate a 2 SIGMA deviation without calculus and don't have the simple formula. For rounding up, I just added another 50% in points to my 1 SIGMA number and figured I might be in a probability of 68 % and 90 % roughly speaking. This gives me a weekly or even two weekly goal to shoot for in index movement, BEFORE putting on an opposing spread. So far in three months I have not seen more than a 17 point, or 3.5 STRIKE swing in the OEX index. Just enough to touch one of my threatened spreads, thats all. Enough to cost big bucks though.
If you are right and the number is away from both sides of the average, then that makes SIGMA value spread trading worthless on the OEX INDEX. You couldn't find any premiums worth trading. Split it is a useful tool for outside goals in a swinging moving index.
--- On Sat, 7/10/10, Lan Sluder <lansluder@gmail.com> wrote:
From: Lan Sluder <lansluder@gmail.com>
Subject: Re: Bz-Culture: 1 Sigma deviation
To:
Cc:
bz-culture@psg.com
Date: Saturday, July 10, 2010, 7:56 AM
It is the deviation on either side. So if the mean is 50, and the deviation is 5, the range at a given probability would be 45 to 55.
--Lan Sluder
On Sat, Jul 10, 2010 at 4:19 AM, Ray Auxillou <hillviewhacienda@yahoo.com> wrote:
Any statistical math people on here?
If I have a 1 Sigma deviation of 6 points. Does that mean 3 on one side of the mean and 3 on the other side of the mean average? Or does it mean 6 points on one side of the mean and 6 points on the other side of the mean?
Probability theory has it that 1 Sigma deviation is a 68 % probability and 2 Sigma deviation has a probability of 95%.
I have a simple formula to calculate the SIGMA but when I get a number of 6.5, I don't know how to apply it on either side of the mean number. Makes a helluva difference in application.