Radio buttons are similar to Check boxes. The difference is that when you specify a group of radio buttons, page visitor can check only one of them, i.e. selecting only one of alternatives is available.
All the buttons in a group of radio buttons must have the same Group Name. Each individual button must have a unique Member Value.
The Name and Value of the form field will be sent to the corresponding CGI.
If you check the Selected member check box, the radio button will be displayed checked in the browser.