Qiang Li

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bio website location age member for 2 years, 9 months seen Aug 24 at 21:16 profile views 35

 Dec15 comment How to test a reduced linear model passing through the origin? +1 Great. Please add some comments and explanation. Thank you. Mar9 comment How to generate uniformly distributed points in the 3-d unit ball? @whuber: is the formula above correct? Mar8 comment How to generate uniformly distributed points in the 3-d unit ball? @mbq: correction, I think the p.d.f is $f_{R, \Theta, \Phi}(r,\theta, \phi)=\frac{3}{4\pi}r^2sin\theta$ Mar8 comment How to generate uniformly distributed points in the 3-d unit ball? @mbq, I think to define the term, we need to have a p.d.f. of $f_{R, \Theta, \Phi}(r,\theta, \phi)=r^2$. Mar8 comment How to generate uniformly distributed points in the 3-d unit ball? @whuber: maybe I just did not get the essence of the previous techniques. Let me try what you described. Additionally, what are the ways to check the uniformity here again? Mar8 comment Determining the nature of noise I like your answer very much. +1 Mar8 comment How to generate uniformly distributed points on the surface of the 3-d unit sphere? I am just wondering if your method of generating points (x,y,z) is essentially the same as whuber's method? Mar8 comment How to generate uniformly distributed points on the surface of the 3-d unit sphere? I bet it is mathematica... just tell from the color... :) Mar8 comment How to generate uniformly distributed points on the surface of the 3-d unit sphere? @whuber: very nice! thanks a lot for your post! "$(X_1/\lambda, X_2/\lambda, X_3/\lambda)$ is uniformly distributed on the sphere." where can I find reference about its proof, or is it simply provable? Mar8 comment How to generate uniformly distributed points on the surface of the 3-d unit sphere? is it possible to post the links where I can find the full text of these references? thanks. Mar7 comment How to generate uniformly distributed points on the surface of the 3-d unit sphere? can any of these projections still preserve the uniformity of randomness? Again, how can I check whether the final distribution of these points are truly uniformly distributed on the surface of the sphere? Thanks.