An opinion poll asks an SRS of 100 college seniors how they view their job prospects. In all, 53 say Good. The sample survey actually called 130 seniors, but 30 of the seniors refused to answer. This nonresponse could cause the survey result to be in error. The error due to nonresponse:_________.
1. is in addition to the margin of error found based on the 100 seniors who answered the poll.
2. is included in the margin of error found based on the 100 seniors who answered the poll.
3. can be ignored because it isn't random.