nanstd use in matlab

Hi, For Matlab, I wonder how to use nanstd to calculate the standard deviation of a 3D matrix with NaN values.

Right now assuming a 3-D matrix A_3D

I used A_std = nanstd(A_3D, [],3);

assuming the first numbers in the 3D matrix is 0.3735 and 0.3477 respectively,

using my code would give me a standard deviation of 0.0182 but in reality, it should be 0.0129, I don't know what is going on and I didn't find answers online

Answer 1

[Chunru]

You are using default normalization "[]", which normalised the std by (N-1). If you want to get 0.0129, you need to change [] into 1.

nanstd([0.3735; 0.3477])

ans = 0.0182

nanstd([0.3735; 0.3477], 1)

ans = 0.0129