Validation radio button

I have a pair of radio buttons where the registrant can choose yes or no, is it possible to set a validation rule, so that he can only continue when he selected yes?
If he selects no is it possible to show a text information?

Thanks

You can definitely set it up to show a Message field by setting the Depends On option in the message field to the [Radio field -> "no"] you've mentioned. You'd probably need to write a custom validation routine to check for the "yes" option being checked before allowing form submission (I think it can be done, and with an hour or two to figure it out I could probably do it, but one of the Devs might be able to give you the code in 30 seconds ).
You could use a required "yes" checkbox instead and just display the "you must select 'yes' to proceed" message all the time.