1-sigma error from data

I have several thousand datapoints that follow a normal distribution (not zero centered and values ranging roughly from -500 to 500).

How can I get the interval from mean-1-sigma to mean+1-sigma?

Answer 1

[Chunru]

x = 500*randn(10000, 1) + 200;          % some data
mx = mean(x);
sx = std(x);

plot(x, 'o'); hold on; grid on;
yline(mx+[-1 0 1]*sx, 'r');