If statements for Yes/No answer

I think my question is fairly simple but I am only starting out.
How do I make an if statement where the question is "Are you registered?" and the options "Yes" and "No"?
I want to give the answer "Yes" a hidden score of "10".
Assistance appreciated

I tried this:
if(#form/#form/centre_registered= 'yes','10')
But received the following:
Parse error on line 1: if(#form//data/centre_regist ---------^ Expecting 'EOF', 'RPAREN', 'OR', 'AND', 'EQ', 'NEQ', 'LT', 'LTE', 'GT', 'GTE', 'PLUS', 'MINUS', 'MULT', 'DIV', 'MOD', 'UNION', 'COMMA', 'SLASH', 'RBRACK', got 'DBL_SLASH'

You are on the right track, but the if() function requires a second argument if the statement is false.

Also, if you intend to use the scores in math in the form it's probably best to use numbers instead of strings as the outputs, so I think you want something like

if(#form/centre_registered= 'yes', 10, 0)

Thanks! Your suggestion worked