## Trying to find the mean and standard deviation without using the built in functions?

### Olivia Colombo (view profile)

on 12 Feb 2019
Latest activity Answered by John D'Errico

on 12 Feb 2019

### John D'Errico (view profile)

I'm new to functions so any help would be appreciated!

### John D'Errico (view profile)

on 12 Feb 2019

You show a function that does it already, although at a quick glance, it appears to compute the standard deviation incorrectly. Is your question how to do it correctly?
First, I would NOT use std as the name of a variable. One day you will want to use the true function std, and you won't be able to, and then you will come back crying about a strange bug. Get used to not naming variables like that.
Some parts of your code were ok. But you already know how to use sum. So use it!
function avgandstd(x)
x = x(~isnan(x));
n = length(x);
avg = sum(x)/n;
S = sqrt(sum((x - avg).^2/(n-1)));
disp(['mean = ',num2str(avg),' and standard deviation = ',num2str(S)])
end