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Ruri
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How can I compare two measurements which are composed of matrices such as [0 1 0 0...]

Asked by Ruri
on 15 Mar 2019
Latest activity Commented on by Ruri
on 19 Mar 2019
I'm currently doing analysis to compare two measurements, so I decided to use cohen's kappa.
The problem is that there are no meaningful values as a result.
For example, I have a two processed data like below.
emg = [0 0 0 0 0 1 1 0 0]; video = [0 0 0 0 0 0 0 0 0];
Do I need to make another row for 0, 1 each?, like
emg = [0 0 0 0 0 0 0 0 0];, emg = [1 1 1 1 1 0 0 1 1];
video = [0 0 0 0 0 0 0 0 0];, video = [1 1 1 1 1 1 1 1 1];
If anyone have an idea about statistical analysis, please give me a hand.

  2 Comments

We don't know enough about your measurements to be able to judge...what is the measurement of and is this a rating system? Cohen's Kappa is to judge consonance between to raters' judgement; doesn't really sound like that's the null hypothesis here.
Yes, I just made some scores from the video which I rated the movement as a number 1. And I also wanted to measure relevance and consistency, kind of like correlation with numeric binary datasets.

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1 Answer

Answer by Jos (10584)
on 18 Mar 2019
 Accepted Answer

You are looking for a measure of consistency between two measurements which are represented as binary vectors of the same length? My idea would be to count the discrepancies between them, and perhaps correct for the number of observations:
emg = [0 0 0 0 0 1 1 0 0]; video = [0 0 0 0 0 0 0 0 0];
fraction_of_discrepancy = sum(abs(emg - video)) / numel(emg)

  3 Comments

Thank you so much for your comment.
After calculating,
[0 0.0138888888888889 0.0138888888888889 0.0138888888888889 0.0138888888888889 0.0138888888888889 0.0138888888888889 0 0 0 0...]
These values are shown up, then '0' means that there is no discrepancy?
I would have expected a single number.
In my formula, a 0 would indeed indicate that the sequences of 0's and 1's are the same in the two vectors.
I think it's because my data(emg and video) is consisted of structures, not the one vector.
It's like '4 x 18 double' each.

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