Since the radio station does not specify a month for the caller's birth date I was approaching the problem with the view of independent events for the caller and the wheel spin, e.g. spinning 2 wheels with 12 months each on them for the same result on each wheel.

There are 12 possibilities for the random caller's birth month, and there are 12 possibilities for the wheel to land on... 1/12 x 1/12 = 1/144 for matching months. Is this wrong? If not, then the same principle would seem to apply to the date wheel as well...

Looking forward to your replies :)

Think of something simpler. You may hold in your hand either a white or a black ball. The radio station manager picks randomly one of two colors. Regardless of which ball you are holding, the probability of a match is 1/2. This is true even if you do not know the color of your ball. It does not matter which ball is in your hand. It will be matched with the probability of 1/2.

Cheers.

This is when the wheel is spun before a call has been made. The caller is then declared a winner if his/her month of birth matches the one that the wheel shows. In this case the probability of the match is indeed 1/12×1/12.

The point of concern was about the probability of matching the month of birth.