Calculate the value of f and its standard error s_{\bar{f}} assuming the standard error of x and y, s_{\bar{x}} and s_{\bar{y}} are independent and random and from the given values and standard errors for x and y.

1. f=x^2 for x=25\pm1

So using the formula we have for it, I get {s_{\bar{f}}}^2={(\frac{\delta f}{\delta x})}^2 s_{\bar{x}}=(2x)^2 s_{\bar{x}}=50s_{\bar{x}}

First, is that correct thus far?
Second, what is s_{\bar{x}}? Is it just the 1 from the \pm 1 in the uncertainty of f?