MATLAB: Thresholding data based on z-score

Question

Hi All,

I'm attempting to threshold my data using their z-score values. However, it's not clear to me how I am meant to get actual z-score values if the zscore function in matlab give me a matrix where the columns are the values 1SD away when the mean is centered at 0. How could I threshold data to identify values with a z-score of 2 when the zscore function seems to give a matrix where all values have a z-score of 1. I might be reading the matrix incorrectly. CouldI please get some help with this?

Best,

Christiane

Answer 1

Try this, assuming a 1-D signal:

zScores = zscore(signal)
% Get indexes where zScores > 2
indexes = zScores > 2;
signalWithZMoreThan2 = signal(indexes);