Answer:
a. When we reject null although it was true.
b. When we fail to reject null although it was false.
Explanation:
A type I error occurs when we reject a null hypothesis when it is actually true.
Thus in this case Type I error will occurs when we have a strong evidence that Buzz a dolphin could communicate. But we still reject this and conclude that it cannot communicate and we are only guessing.
Type II error occurs when we fail to reject a null hypothesis although it is false. So when we do not have a strong evidence that Buzz the dolphin can communicate and we still conclude that it can, it is said that we have incurred type II error.
