Question

Suppose we have a qubit in the state |ψ>. We know that if we measure it in the standard basis, the probability of getting a 0 is 7/9. Now, if we instead first apply a Hadamard gate and then measure the resulting qubit H|ψ> in the sign basis, what is the probability of getting a +?

Answer 1

7/9

Answer 2

2/9 is correct