Assume that we observe three draws, X1,X2,X3 from a Bernoulli distribution with parameter p=12. For example, imagine that in the model for the preferred head direction for kissing, either direction were actually equally likely and we observed three kissing couples.

Question

What is the probability of observing at least two ones, i.e., what is P(∑3i=1Xi≥2)?

Answer 1

0.25

Answer 2

0.5