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Aug
8
awarded  Yearling
Nov
22
answered Why is an inverted yield curve a problem?
Oct
25
revised How many explanatory variables is too many?
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Aug
15
comment How many explanatory variables is too many?
The bullet point after "within the range of the data" means don't extrapolate. That's different than out-of-sample. Key point there is does not affect $\hat{y}$ ....
Aug
15
comment How many explanatory variables is too many?
"The holdout sample won't necessarily catch multicollinearity" is precisely right. And irrelevant for prediction. A random Google search confirms, with among others "If interest is only in estimation and prediction, multicollinearity can be ignored" public.iastate.edu/~alicia/stat328/Model%20diagnostics.pdf
Aug
15
comment How many explanatory variables is too many?
The point is that you arrived at humidity down/uptown by trying out a bunch of regressors and chancing on one that fit that dataset. Therefore, the holdout sample is unlikely to show the regressor as being good, and you'll see the problem. If it does work in the holdout sample, maybe you've just found a new regressor that actually does work. It doesn't matter whether it's causal or not--for prediction covariance is good enough as long as it consistently covaries.
Aug
15
comment How many explanatory variables is too many?
You want to know how it performs out-of-sample. Therefore you agree in advance that when developing your model you will only use, say 2/3 of your data. That tricks nature into giving you 1/3 of your data as out-of-sample data that you actually can observe. This is a common technique in predictive applications, and it works quite well when you've got a lot of data--as is likely the case here.
Aug
14
comment How many explanatory variables is too many?
This is a good start, but ultimately it's still in-sample. If what you're interested in is prediction, it's hard to beat actually predicting out-of-sample and seeing how good it gets. Since you don't care about the coefficients just the results, avoiding multicollinearity isn't really the answer here.
Aug
13
answered How many explanatory variables is too many?
Aug
11
awarded  Self-Learner
Aug
10
answered What data sources are available online?
Aug
10
awarded  Scholar
Aug
10
accepted Closed-form formula for approximate maximum duration of a bond?
Aug
10
awarded  Teacher
Aug
10
comment Modified Durations of Different Noncallable Bonds and function of Maturity
The horizontal asymptote will always be at duration=(1 + 1/i) where i is the current market interest rate expressed in proportion terms (e.g. i=.05 for a 5% rate).
Aug
10
comment Modified Durations of Different Noncallable Bonds and function of Maturity
See the answers to this question about how to calculate the maximum duration for some more references and graphs: quant.stackexchange.com/questions/1624/…
Aug
10
revised Closed-form formula for approximate maximum duration of a bond?
added 7 characters in body
Aug
10
revised Closed-form formula for approximate maximum duration of a bond?
solution
Aug
9
revised Closed-form formula for approximate maximum duration of a bond?
added 9 characters in body
Aug
9
comment Closed-form formula for approximate maximum duration of a bond?
Thanks for this. I'm still sorting through all this, but in re-reading both the Pianca paper and the Hawawini paper I am starting to realize that my previous lack of progress on this issue results from my assumption that the closed-form formulae for duration were approximations. By contrast, Pianca seems to use them as though they are exact. I'll have to work through the derivations and figure out whether they are, in fact, exact. If so, I can likely avoid the whole iterative algorithm and just go directly from maturity to duration.