How may bias arise in a statistical investigation?

I am currently doing my stats GCSE coursework and one part of is that I have to write about how bias could be caused, the investigation is into the theme of reaction times, in which people are made to take a quick test (game) that measures their reaction times it is then sent via the internet onto a database and then sent to me once all collected, how may bias have arisen in this investigation?


Thank you|||One way that bias could enter would be if you didn't pick a random sample of responders. In other words, if you only selected experienced video gamers who have developed the skill at a high level, or if you selected people who had vision problems and couldn't see the screen very well, and you want to generalize your results to the general public, you'd have a biased sample.