# Define the name and parameter(s) of the procedure.
__f__ := proc(__l__::list(numeric))

# Define variables that are local to the procedure.
        local __avg__, __i__;

# Define the statements of the procedure.
        __avg__ := add(__l__[__i__], __i__ = 1..nops(__l__))/nops(__l__);

# Define the return value of the procedure.
        return __avg__;

end proc;

$f:=\mathbf{proc}\left(l::\left(\mathrm{list}\left(\mathrm{numeric}\right)\right)\right)\mathbf{local}\mathrm{avg}\,i\;\mathrm{avg}:=\mathrm{add}\left(l\[i\]\,i\=1..\mathrm{nops}\left(l\right)\right)\/\mathrm{nops}\left(l\right)\;\mathbf{return}\mathrm{avg}\mathbf{end\; proc}$

__f__([1, 2, 4, 8, 16, 32, 64]);

$\frac{127}{7}$