Given that:
- Each attendee is given a number at a convention.
- A number is randomly selected.
- The person with that number wins a laptop.
You need to remember that, by definition:
- When a part or parts of a population have more chances of being selected over others, then the sample is biased.
- When each part of a population has the same chance of being selected, then the sample is unbiased.
In this case, you know that each attendee at the convention receives a number. Therefore, each attendee has the same chance of being selected and winning the laptop. Then, you can determine that it is an unbiased sample.
Hence, the answer is: Unbiased.