It's important to identify potential sources of bias when planning a sample survey.
When we say there's potential bias, we should also be able to argue if the results will probably be an overestimate or an underestimate.
Try to identify the source of bias in each scenario, and speculate on the direction of the bias (overestimate or underestimate).
Scenario 1

David hosts a podcast and he is curious how much his listeners like his show. He decides to start with an online poll. He asks his listeners to visit his website and participate in the poll.
The poll shows that
89%, percent of the 200 respondents "love" his show.
QUESTION A
What is the most concerning source of bias in this scenario?

Choose 1

(Choice A)
A
Response bias

(Choice B)
B
Undercoverage

(Choice C)
C
Voluntary response sampling