Answer
$0.167$
Work Step by Step
1. Allow each person to have any day as birthday, we have the total outcomes $T=365^{12}$,
2. The permutation $P(365,12)$ represents no two people have the same birthday,
3. Thus the probability that at least 2 people have the same birthday is given by
$p=1-\frac{P(365,12)}{365^{12}}\approx0.167$
