Sometimes things are better explaned in examples rather than definitions, so here is an example-
Bias- If given a choice, Coach Bob prefers to chose boys for his team because that is who he prefers to work with. He has coached both boy and girl teams but thinks boy teams are easier to coach based on his past experiences. There were personal experiences that influenced this bias. Because of this bias, he may miss out on coaching an awesome group of girls because every group is different. If Bob recognizes that he feels a positive bias towards boys and negative bias towards girls, he might want to pay extra attention to not let his bias affect his decisions.
Prejudice- Coach Bob choses boys for his team because he believes girls are inferior. He believes that girls are weaker and disorganized. He believes this is fact. He did not himself have negative experiences with girls, but his dad told him girls were weak, and his grandpa said girls were weak, and his uncle said girls were weak, so it just seems to be common knowledge. Bob may not even recognize that he is prejudiced. He will likely miss out on working with an awesome team of girls because he has a deep belief that are inferior.