how do i calculate the Correlation coefficients

I have dataset that contains the acceleration data of three axes (x, y, and z) , this an example of my data

   X                 Y                Z

 %1.0195313  0.16088867  -0.26391602

 %1.0976563   0.17456055  -0.33447266

 %1.2556152  0.24926758  -0.3774414

 %1.2314453  0.517334  -0.25732422

 %1.0212402  0.5761719  -0.09277344

 %1.0727539  0.51000977  0.007324219

 %1.1694336  0.32885742  -0.017822266

 %1.1247559  0.22924805  -0.10595703

 %1.0339355  0.27905273  -0.13623047

 %0.8273926  0.24560547  -0.080566406

 %0.75097656  0.25390625  -0.018310547

 %0.67626953  0.3046875  0.051757813

 %0.7282715  0.33764648  0.08911133

 %0.8227539  0.34545898  0.08325195

 %0.87939453  0.3413086  0.08300781

 %1.0527344  0.34326172  0.106933594

 %1.1125488  0.32128906  0.10058594

 %1.1477051  0.26416016  0.06347656

 %1.2807617  0.2680664  0.015136719

 %1.2800293  0.2668457  -0.006347656

I have calculated the Correlation coefficients of two axes (x and y) using the corrcoef function as illustrated bellow

     R = corrcoef(X_Segments{1},Y_Segments{1})

X_Segments contains data of the first column (X Data) and Y_Segments contains data of the second column (Y Data). However, the output was strange

    R =

    1.0000    0.3424
    0.3424    1.0000

I want to know which value represents the Correlation coefficients between X and Y and is there any solution to get the Correlation coefficients between two axes directly as one value (single output) not as a matrix ?

Answer 1

[neamah al-naffakh]

Hi guys, thanks for your answer howeover, the correct function is corr

    CorrcoeffXY{nn,1} = corr(X_Segments{nn},Y_Segments{nn});

and the output will be the Correlation coefficients between X and Y

R = 0.3424

[the cyclist]

Oh, of course. I only tried

corr(rand(5,2))

(which returns a matrix)

and not

corr(rand(5,1),rand(5,1))

(which returns a scalar).

Glad you found something that worked for you.

Answer 2

[the cyclist]

The upper-right and lower-left elements are equal, and each one is the correlation you want. The diagonal elements are the trivial correlation of X with itself and Y with itself. Those will always be equal to 1, by construction.

I don't think there is a simple way to get just the single number without first getting the matrix.

[Image Analyst]

So, (just to be super explicit)

 correlationBetweenXandY = R(1,2);

Is that what you want neamah?