Indeed. I like to say, we would like three things to be true:
1) Every day has 86400 seconds.
2) Every day is from noon (sun exactly above) to noon (sun exactly above).
3) We use SI seconds.
You can't have all three. Pick any two:
1, 2, not 3: What you describe. Day has 86400 seconds, we keep in sync with the sun, but we tweak the seconds a bit. There are different versions, like epoch time, or UT1.
1, not 2, 3: Every day has 86400 SI seconds, and we slowly go out of sync with the sun. That's TAI.
not 1, 2, 3: We use SI seconds and keep in sync with the sun +/- 1 second, but need to add/drop seconds occasionally. That's UTC.
Not really. It's still the standard deviation, and it still gives you bounds on probability, for example the Chebyshev inequality:
P(|X-\mu| > k \sigma) < 1/k^2.
So, while for a normal RV, 5% of observations lie outside +/- 1.96 std.devs, for arbitrary RV (with finite variance) at most 25% of observations lie outside +/- 2 std.devs.
Even with equities, things are not entirely trivial.
A few examples: Some stocks trade in one currency, but pay dividends in a different currency. Some stocks go ex-div before the dividend amount has been determined (e.g. in Japan). Stocks trade on certain days, and trades settle on certain days, and they might be subject to different holiday calendars. Corporate actions are not entirely trivial, either (with rights issues, you need to issue two temporary securities for accounting purposes, etc.).
Well, that's not money created out of nowhere. The balance sheet extension creates money and an equivalent liability. That's the point of the statement, not money supply and its regulation.
> If someone sells you 12345.55 EUR vs USD at a rate of 1.12345, how many EUR do you think you end up with?
1. If someone sells me 12345.55 EUR, I hope to end up with 12345.55 EUR.
2. That's the point though. They will sell you a certain amount of EUR at a certain dollar price. This, in turn, implies a rate (which might well have more than 5 digits behind the decimal). This is ideally close to the quoted rate, sure. But what counts is the actual EUR amount and the actual USD amount, not what rate was quoted or with how many digits.
> you're interested in the risk metrics, like durations, convexity, vega, and so on, no one cares what your rounding convention is. doubles are just fine, thank you.
Doubles are not just fine, but required there. If you compute risk, as you allude to, by finite differences, then you need the precision of floats rather than rounding to integer cents prematurely.
Sorry, that strikes me as the norm. Graduation is predicated on passing certain courses, and obviously you can't take it an arbitrary number of times. So fail an exam twice, and you're out. (Some universities offer a final oral exam after failing a written exam twice.)
Indeed. Early to mid 1990's, that's where it was at. FTP, telnet, gopher were awesome, and then, in short order: HTML, Mosaic, Netscape - the WWW. Really useful.
Then AOL etc. offered cheap dial-up, and suddenly you had all those noobs online ("Eternal September"). Been going downhill since then ;-)
You’ll hear about deadly small plane accidents, and about accidents of large planes, but are unlikely to hear about harmless accidents with small planes. Just not interesting. But they happen all the time.
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