How to calculate the standard deviation of individual points in a dataset

Hi, I'm still learning how to use Matlab and I'm having challenges plotting an error bar. It seems to be from my calculated standard deviation. I want to plot an errorbar with x against y and showing the standard deviation of y

x=[0.1:0.3]; y=[37.9, 31.9,34.6]; xy=[x,y] sd=std(xy) errorbar(x,y,sd, 'bp')

I also tried std(x,y) but it didn't work either.

Answer 1

[Star Strider]

The standard deviation of a point is 0.

The size of ‘sd’ here must be the same size as both ‘x’ and ‘y’ so ( vertically concatenated ‘x’ and ‘y’ to have something the std function can work with (although this is likely not correct from a statistical perspective). I also supplied a ‘step’ of 0.1 for ‘x’ so it will be the same length as ‘y’.

x=[0.1:0.1:0.3];
y=[37.9, 31.9,34.6]; 
xy=[x;y]; 
sd=std(xy); 

figure
errorbar(x,y,sd, 'bp')
xlim([0 0.4])

I invite you to experiment with these functions.

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[Chiamaka Onwude]

It worked. Thank you very much

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

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