Add training workflow, datasets, and runbook
This commit is contained in:
@@ -0,0 +1,38 @@
|
||||
808 Part VI: Measuring and Trading Volatility
|
||||
of them resulted in the stock being unchanged. Also, only about 2,500 or them, or
|
||||
1110th of one percent, resulted in a move of-4.0 standard deviations or more. Those
|
||||
percentages, along with all of the others, would be built into the computer, so that
|
||||
the total distribution accounts for 100% of all possible stock movements.
|
||||
Then, we tell the computer to allow a stock to move randomly in accordance
|
||||
with whatever volatility the user has input. So, there would be a fairly large proba
|
||||
bility that it wouldn't move very far on a given day, and a very small probability that
|
||||
it would move three or more standard deviations. Of course, with the fat tail distri
|
||||
bution, there would be a larger probability of a movement of three or more standard
|
||||
deviations than there would be with the regular lognormal distribution. The Monte
|
||||
Carlo simulation progresses through the given number of trading days, moving the
|
||||
stock cumulatively as time passes. If the stock hits the break-even price, that partic
|
||||
ular simulation can be terminated and the next one begun. At the end of all the tri
|
||||
als (100,000 perhaps), the number in which the upside target was touched is divided
|
||||
by the total number of trials to give the probability estimate.
|
||||
Is it really worth all this extra trouble to evaluate these more complicated prob
|
||||
ability distributions? It seems so. Consider the following example:
|
||||
Example: Suppose that a trader is considering selling naked puts on XYZ stock,
|
||||
which is currently trading at a price of 80. He wants to sell the November 60 puts,
|
||||
which expire in two months. Although XYZ is a fairly volatile stock, he feels that he
|
||||
wouldn't mind owning it if it were put to him. However, he would like to see the puts
|
||||
expire worthless. Suppose the following information is available to him via the vari
|
||||
ous probability calculators:
|
||||
Simple "end point" probability of XYZ < 60 at expiration: 10%
|
||||
Probability that XYZ ever trades < 60 (using the lognormal distribution) 20%
|
||||
Probability that XYZ ever trades < 60 (using the fat tail distribution): 22%
|
||||
If the chances of the put never needing attention were truly only 10%, this trader
|
||||
would probably sell the puts naked and feel quite comfortable that he had a trade
|
||||
that he wouldn't have to worry too much about later on. However, if the true proba
|
||||
bility that the put will need attention is 22%, then he might not take the trade. Many
|
||||
naked option sellers try to sell options that have only probabilities of 15% or less of
|
||||
potentially becoming troublesome.
|
||||
Hence, the choice of which probability calculation he uses can make a differ
|
||||
ence in whether or not a trade is established.
|
||||
Other strategies lend themselves quite well to probability analysis as well.
|
||||
Credit spreaders - sellers of out-of-the-money put spreads - usually attempt to quan
|
||||
tify the probability of having to take defensive action. Any action to adjust or remove
|
||||
Reference in New Issue
Block a user