Why am I getting this error message?

function [STD] = STD(T4, T7, H2O, Temp4, Temp7, H2Onumb, HC)

s4 = (T4/Temp4)^2; %std of T4 divided by the mean of T4
s7 = (T7/Temp7)^2; %std of T7 divided by the mean of T7
sH2O = (H2O/H2Onumb)^2; %std of H2O divided by the mean of H2O
STD = HC*(sqrt(s4+s7+sH2O)); %Standard Deviation of Heat Capacity value

Not sure why the error came up. It worked once but then this error message pops up after every attempt.

Answer 1

[James Tursa]

Don't post images of code. This makes it impossible for readers to copy & paste your code for testing. Instead, post the actual text of the code & error messages etc and then highlight this text and press the { } Code button to format it.

You have a function named STD and a variable named STD. These conflict with each other. As soon as you define the variable STD in the workspace, it shadows the function. Choose a different name for the variable.