Timeline for Including errors in perpendicular off-set determination of points from a line
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Sep 20, 2015 at 16:24 | comment | added | Creosote | Let us continue this discussion in chat. | |
| Sep 20, 2015 at 15:25 | comment | added | Creosote | See end of updated post. | |
| Sep 20, 2015 at 15:24 | history | edited | Creosote | CC BY-SA 3.0 |
answered a comment with supplementary material
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| Sep 20, 2015 at 14:04 | comment | added | Dalek | Thanks a lot but I can not follow the math. How did you obtain the first equation? | |
| Sep 20, 2015 at 13:54 | history | undeleted | Creosote | ||
| Sep 20, 2015 at 13:54 | history | edited | Creosote | CC BY-SA 3.0 |
rewrite
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| Sep 20, 2015 at 11:42 | history | deleted | Creosote | via Vote | |
| Sep 20, 2015 at 10:59 | comment | added | Creosote |
I could've put more comments in the code ... The black points are the true (but unseen) $x$ and $y$ values, deliberately chosen to be perfectly linear. The red circles are the observed versions of $x$ and $y$, i.e. with added "uncertainty" (Normal errors). The red lines drop down to the most-probable point on the black line. If you changed the code to sd_x=rep(2,n); sd_y=rep(0.2,n) in the relevant place, you'll see that the projections are obviously better than perpendicular would have been.
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| Sep 20, 2015 at 10:13 | comment | added | Dalek | it doesn't seem the black points are the perpendicular projections of the red points on the line. | |
| Sep 20, 2015 at 9:53 | comment | added | Creosote | They're projections onto the "best" point on the black line. If the sd_x and sd_y values are equal for a data point, that projection should be perpendicular to the black line, or I messed up my code. | |
| Sep 20, 2015 at 9:47 | comment | added | Dalek | are the red lines representing the distances has been computed as perpendicular distances? | |
| Sep 19, 2015 at 21:31 | comment | added | Dalek |
I appreciate your answer but I am not very familiar with R but I know python. It would be absolutely great if you could post your example by python too, or write just the math if you think it is sufficient.
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| Sep 19, 2015 at 21:12 | history | answered | Creosote | CC BY-SA 3.0 |