standard deviation in errorbar

[a very silly question!] How to calculate the errorbar with 2 standard deviations in this example?

x=1:10;
y=rand(10,50);
errorbar(x, mean(y,2), std(y,[],2)) % 1 standard deviation

Just multiplying std by 2 in the errorbar, right?

errorbar(x, mean(y,2), 2 * std(y,[],2))

Answer 1

[Star Strider]

Not silly at all, however it may not produce the result you want.

It might be more appropriate to calculate the errors as the standard error of the mean (S.E.M.) :

err = 2*(std(y,[],2)/sqrt(size(y,2)));                  % 2 x Standard Error Of The Mean

then:

figure
errorbar(x, mean(y,2), err) % 2 standard errors of the mean

rather than the standard deviation of the observations themselves.

[Sim]

Thanks a lot @Star Strider, very kind!

@Rik: many thanks for your reply too, even though I cannot see it anymore!

P.S.: I would have accepted both answers!

[Star Strider]

As always, my pleasure!

[Rik]

You're welcome.

(I deleted my answer as it overlapped with this answer too much, and this one was better)

[Star Strider]

@Rik — I very much appreciate your compliment!