Using Button Group in MATLAB GUI

Hi,

I am trying perform this action using MATLAB GUI: i) Create a button group with 2 radio button ii)Based on user's selection, a variable (say, num) gets assigned a value ('1' for radiobutton1 and '2' for radiobutton2) iii) Output this variable with the user's selection to MATLAB workspace using OutputFcn

I am able to assign a value based on user selection to 'SolutionMethod', but I get an error in the OutputFcn: _ Error in ==> TrialGUI3>TrialGUI3_OutputFcn at 91 function varargout = TrialGUI3_OutputFcn(hObject, eventdata, handles)_

Questions:

1) How do I remove error?

2) How do I get the value of 'num' variable to MATLAB workspace?

Here's my MATLAB code:

% ---------------------------------------------------------
% Executes just before TrialGUI3 is made visible.

function TrialGUI3_OpeningFcn(hObject, eventdata, handles, varargin)

% Choose default command line output for TrialGUI3
handles.output = hObject;  
set(handles.uipanel1,'SelectionChangeFcn',@uipanel1_SelectionChangeFcn);

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes TrialGUI3 wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Executes when selected object is changed in uipanel1.
function uipanel1_SelectionChangeFcn(hObject, eventdata, handles)

switch get(eventdata.NewValue,'Tag') 
% Get Tag of selected object.
    case 'radiobutton1'
        % Code for when radiobutton1 is selected.
        num = 1;   
        disp(num);
    case 'radiobutton2'
        % Code for when radiobutton2 is selected.
        num = 2;
        disp(num);
    otherwise
        % Code for when there is no match.
end
guidata(hObject,handles);

% --- Outputs from this function are returned to the command line.
function varargout = TrialGUI3_OutputFcn(hObject, eventdata, handles) 

% varargout{1} = output.handles;

% --------------------------------------------------------------
% uipanel1: Tag for button group
% radiobutton1: Tag for radio button 1
% radiobutton2: Tag for radio button 1

Thanks in advance for your help.