1.Only claims that can be objectively verified can be trusted.

2.Many people have reported encounters with ghosts.
3. So the existence of ghosts is likely to be true.

1. acceptable by observation
2. acceptable by testimony
3. unacceptable by testimony

I was asked to state the premise acceptability/unacceptability and conditions of it. I just want to double check if I did it right.

Did you reach a conclusion? Is the testimony acceptable or unacceptable? Does the testimony constitute objectively verifiable observation? I think you need to define what objective verification is.