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Oct
15
comment Estimate error on slope of linear regression given data with associated uncertainty
I'm not saying it's required; you're the only one who is supposed to determine whether they should be accounted for or ignored. My point was that weighted orthogonal regression (which accounts for errors in both coordinates) is a tougher problem to solve (and thus requires more elaborate methods) than weighted linear regression, which is easily handled by the built-in function LinearModelFit[] (via its Weights option).
Oct
15
revised Vectors with a certain magnitude in Mathematica
added demonstration of von Mises-Fisher
Oct
15
comment Estimate error on slope of linear regression given data with associated uncertainty
@George, that is a very important piece of detail. Please edit your question to mention that both your abscissas and ordinates have associated errors.
Oct
15
revised Fixed color scale in multiple density plots
edited tags
Oct
15
comment Estimate error on slope of linear regression given data with associated uncertainty
If I understand you correctly, your data is of the form $(x_k,y_k,\sigma_k)$, where $(x_k,y_k)$ is a data point, and $\sigma_k$ is the associated uncertainty (meaning your $y_k$ is actually the interval $y_k\pm\sigma_k$)?
Oct
15
revised Estimate error on slope of linear regression given data with associated uncertainty
edited tags
Oct
14
revised 2 non-linear equations with 2 unknowns which I cannot solve
edited tags
Oct
14
comment NDSolve runs out of memory
@drN, yes, you still expend the same amount of effort; after all, you still have to do all those evaluations to get to where you want to be.
Oct
14
revised Creating randomly oriented planes
added 21 characters in body
Oct
14
revised Vectors with a certain magnitude in Mathematica
edited tags
Oct
14
answered Vectors with a certain magnitude in Mathematica
Oct
14
comment Vectors with a certain magnitude in Mathematica
Note the clumping of points on the left point-cloud; this shows that the distribution followed by Normalize[RandomReal[{-1, 1}, 3]] is not uniform over the surface of the sphere.
Oct
14
comment Vectors with a certain magnitude in Mathematica
This paper discusses the last method that David supplied.
Oct
14
comment Vectors with a certain magnitude in Mathematica
Relevant math.SE question.
Oct
14
answered Calculate proportion of values for dates
Oct
14
revised Calculate proportion of values for dates
added 2 characters in body
Oct
14
comment Calculate proportion of values for dates
Okay, to summarize: you want a count (and from there the proportion) of the number of "cold" days for each month, for all those years?
Oct
14
comment Calculate proportion of values for dates
I'm getting confused... by "date", did you mean "month"? There is only one (mean) temperature assigned to each date; for each month, the number of temperature values corresponds to the number of days (of course).
Oct
14
revised Problem with Financial Data
added 332 characters in body
Oct
14
comment Calculate proportion of values for dates
To compute the proportions for all the months of those years: Map[Count[#, {d_List, t_?Negative}]/Length[#] &, SplitBy[cityTemp, {#[[1, 1]] &, #[[1, 2]] &}], {2}]