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I'm reading a book on data-analysis and in my book I have the following picture of 3-dimensional data and its scatter plot:

3D data and scatter plot

Could anyone help me understand how is the scatter plot interpreted? It confuses me at the moment...in other words: "How to read the 3D scatter plot?"

UPDATE:

I used the advices given to me by users a.desantos and JTT and I colored half of the scatter plot in the following way:

enter image description here

I wonder if I got it?

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  • $\begingroup$ On 3d scatterplots, always request spikes (projection connectors) to one of the 3 planes, typically, the "floor" one. $\endgroup$ – ttnphns Aug 16 '18 at 10:56
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3D-scatterplots are sometimes a bit confusing, especially if you can't rotate the plot around. However, the scatterplot matrix supports the interpretation, at least here, rather nicely, even if it is missing the colors.

As a.desantos already pointed out, the individual scatterplots in the second image are projections on different planes. If you think how the points in the 3D-scatterplot have to be located in order to give these projections, it maybe becomes clearer.

The projection to the plane x1, x3 would look roughly like this (can't get the image to load up, colors are marked with letters as follows: r=red, g=green, y=yellow, b=blue):

X3 |y y y y y b b b b b
   |y y y y y b b b b b
   |y y y y y b b b b b
   |y y y y y b b b b b
   |y y y y y b b b b b 
   |r r r r r g g g g g
   |r r r r r g g g g g
   |r r r r r g g g g g
   |r r r r r g g g g g
   |r r r r r g g g g g
   +-------------------
                     X1
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    $\begingroup$ Your patient in plotting with chars is awesome and valuable! $\endgroup$ – a.desantos Sep 20 '13 at 8:07
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I think there are missing colours on the second image. They are the projections on the different planes $x_1,x_2,x_3$.

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

  • $\begingroup$ +1 Thank you for your help @a.desantos I think I got it, I added a new picture to verify if I understood the point :) $\endgroup$ – jjepsuomi Sep 20 '13 at 8:04
  • $\begingroup$ At present your answer is a little brief and seems more like a comment; please see if you can expand on it. $\endgroup$ – Glen_b May 23 at 1:09

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