Name Lookup and class scope

Why is it that the return type of setVal is of type string and the parameter type is of type double

typedef string Type;
Type initVal(); 
class Exercise {
public:
    typedef double Type;
    Type setVal(Type); 
    Type initVal(); 
private:
    int val;
};

Type setVal(Type parm) {  
    val = parm + initVal();    
    return val;
}