Based on the context and the answer, generate a question. 

Context: I believe in ghosts but the question is do you believe in ghosts ? I believe in ghosts because I have had many times where there was no explanation to how some things happened at my house . One time I was all alone and my dog was laying next to me and I heard a dog chain rattling and a dog running up the stairs but there was no other dog or person in the house . One night I also heard a dog bark that did not sound like my dog when I was laying down and the bark came from inside my house .

Answer:

They had experienced unexplained events .



Why do they believe in ghosts ?