# Standard Error; A fairly simple question

#### The_Cat

##### New Member
Hello All,

Just a little something I am unsure about, I hope you can help!

So, If you have a pile of averages (say stem weight and root weight) and so you have two seperate standard errors. Now I want a standard error for the total weight, can I just add the two standard errors and have my standard error for the total weights?

Cheers,
The_Cat

#### Dason

Let $$s_w$$ be the standard error of the stem weight and $$s_r$$ be the standard error of the root weight. Then the standard error of the sum is given by: $$s_{w+r} = \sqrt{s_w^2 + s_r^2}$$.