15,161 reputation
12986
bio website quantdec.com
location Northeastern US
age 14
visits member for 2 years, 7 months
seen Aug 27 at 19:17

Consultant (environmental and spatial stats a specialty), expert witness, and teacher. I can be reached through (outdated but still valid) links posted on my web site.

Twitter: @WilliamAHuber // ASA-P website: http://amstatphilly.org/


Why waste time learning, when ignorance is instantaneous?

--T(iger) Hobbes.

For any complex problem there is a simple solution. And it's always wrong.

--[Mis?]attributed to H.L. Mencken by Dava Sobel, Longitude.


Nov
7
comment NMinimize usage
@Frederik You are right: I made that typo early on and because everything worked, I did not catch it. Your suggestion $x = 1+y^2$ accomplishes what was intended and everything goes through as planned. Thank you for reading this post so carefully and well!
Nov
7
awarded  Nice Answer
Oct
24
comment Insert $+$, $-$, $\times$, $/$, $($, $)$ into $123456789$ to make it equal to $100$
@xzczd Thank you! That is a useful insight and looks to be a likely explanation for the failure.
Oct
5
awarded  Nice Answer
Aug
24
awarded  Good Answer
Aug
3
awarded  Nice Answer
Jul
6
awarded  Nice Answer
Jun
12
awarded  Good Answer
Jun
11
awarded  Enlightened
Jun
11
awarded  Nice Answer
May
24
comment AstronomicalData and Planetary Heliocentric (x,y,z) Velocity Components
+1 Consider a central difference instead: it should be more accurate. It makes a substantial difference, by the way: it affects the third sig. fig. in your example, because it reflects the net planetary acceleration during the course of 12 hours.
May
24
comment How to calculate the volume of a convex hull?
That doesn't quite seem to be a duplicate, @andre, because there the data are given in a different form. In principle there should be a formula for computing the volume in terms of a suitable integrals over the curve.
May
24
awarded  Nice Answer
May
23
comment Finding integral points on a surface
The equation is a cubic (parameterized by $n$), so it's possible a more efficient method to obtain all solutions can be found by computing generators of its group of integral points. But typically these groups are so small--I haven't found one larger than $12$ yet--as a practical matter it might not be worth the effort.
May
23
revised Finding integral points on a surface
added 12 characters in body
May
23
revised Finding integral points on a surface
added 217 characters in body
May
23
comment Finding integral points on a surface
You're welcome. You shouldn't be so quick to accept this answer, though: this community does a great job of improving answers over the course of a day or two. Much better answers might appear soon :-).
May
23
revised Finding integral points on a surface
added 935 characters in body
May
23
answered Finding integral points on a surface
May
22
comment CorrelationTest small bug?
It seems to me they are testing the same hypotheses but are using different approximations to the sampling distribution of the test statistic.