Are the Hi-Lo indices in PBJ truncated or floored?
Thanx in advance.
Are the Hi-Lo indices in PBJ truncated or floored?
Thanx in advance.
> Are the Hi-Lo indices in PBJ truncated or floored?
Truncated. They used to be rounded. See pp. 253-54 for the explanation of how Wong changed his methodology for the new edition of the book, in 1994.
Don
> Truncated. They used to be rounded. See pp. 253-54 for
> the explanation of how Wong changed his methodology
> for the new edition of the book, in 1994.
> Don
This might be another silly question but when I read what he said there and that he increased "all" the negative numbers by 1 I guess I assumed maybe he used to floor but I guess you're saying that rounding would also increase all negative indexes by 1? Would changing from rounding to truncating likely change any + index numbers?
But basically you're saying Wong's index numbers would be based on having that huge frequency range around TC0 (-0.999 to +0.999 all would be a TC0?)?
I thought maybe you said somewhere flooring was for some reason more generally done these days, the "default" or in the absence of any other knowledge, to be "assumed", and that in your book BJAIII all the tables were indeed based on Hi-Lo indexes that were floored? If so, would that mean anyone learning indexes from Wong's PBA post-1994 would be just that much off if using your tables - maybe in other words your CH10 tables actually are based on different index assumptions compared to Wong's book?
Just curious - maybe there's other stuff going on too I likely wouldn't understand even if you told me like half-deck assumptions or something or that your 6-8 index table on p 213 is different from Wong's just becasue it's 6 or 8 decks and in my Wong book he only does 1D and 4D indexes.
Not that anybody did anything wrong or maybe even that any of this likely matters from a practical point of view that much anyway.
Maybe the moral is to make an effort to learn as closely as you can what assumptions were behind the index numbers you're learning and, if you ever use a sim, make sure you tell it to do it the same way or something.
All of which pales in comparison to the really important question. Is it indexes or indices?
> This might be another silly question but when I read
> what he said there and that he increased
> "all" the negative numbers by 1 I guess I
> assumed maybe he used to floor but I guess you're
> saying that rounding would also increase all negative
> indexes by 1?
No, that wouldn't be true. I didn't used to think that Wong floored, in the first book, but rounding negative numbers would sometimes give the SAME value as truncating, so maybe you're right.
>Would changing from rounding to
> truncating likely change any + index numbers?
Yes, for sure. So, it appears that Wong used to floor and then changed to truncating. For some reason, that surprises me.
> But basically you're saying Wong's index numbers would
> be based on having that huge frequency range around
> TC0 (-0.999 to +0.999 all would be a TC0?)?
For now, yes. The thing is, in all of his very early newsletters and simulations, he always truncated, so it's confusing.
> I thought maybe you said somewhere flooring was for
> some reason more generally done these days,
It is.
> the
> "default" or in the absence of any other
> knowledge, to be "assumed", and that in your
> book BJAIII all the tables were indeed based on Hi-Lo
> indexes that were floored?
Right. But you can't assume that others do that, too. There's no consensus.
> If so, would that mean
> anyone learning indexes from Wong's PBA post-1994
> would be just that much off if using your tables -
> maybe in other words your CH10 tables actually are
> based on different index assumptions compared to
> Wong's book?
Yes, they were generated with flooring and Wong's aren't. Not a big deal, though.
> Just curious - maybe there's other stuff going on too
> I likely wouldn't understand even if you told me like
> half-deck assumptions or something or that your 6-8
> index table on p 213 is different from Wong's just
> because it's 6 or 8 decks and in my Wong book he only
> does 1D and 4D indexes.
Well, that, too, but all the differences are very small.
> Not that anybody did anything wrong or maybe even that
> any of this likely matters from a practical point of
> view that much anyway.
Exactly. Just different methodologies, each valid.
> Maybe the moral is to make an effort to learn as
> closely as you can what assumptions were behind the
> index numbers you're learning and, if you ever use a
> sim, make sure you tell it to do it the same way or
> something.
Exactly right.
> All of which pales in comparison to the really
> important question. Is it indexes or indices?
Ha! Just the English vs. Latin plural. When "index" means "a number," such as in BJ, either plural is perfectly acceptable. But, when "index" means an alphabetized list at the back of a book, then you need to say "indexes."
Don
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