You are biased TOWARDS something, but you are prejudiced AGAINST something But if you are simply stating that something is not neutral (but not indicating the direction of favour), either can theoretically be used. "The court was biased" "The appraisal was prejudiced". The adjectives are synonyms. However, in modern usage, "prejudiced" has a fairly strong negative connotation in all common uses, whilst "bias" is a bit more flexible in how judgemental the connotation will be depending on the context

They are both words conveying skewed feelings towards a certain type of people. But they differ in that bias is a positive sentiment while prejudice a negative one. “My daughter is the prettiest girl in the world, but I’m her dad so I’m biased.” “She is prejudiced against people who are...”

Acccording to my use and the dictionary, you can be biased in favor or biased against. Prejudice has a legal meaning as both a noun and a verb which isn't related to the adjective form.

Prejudice is having a opinion that is not based on fact or experience or is made before learning sufficient facts. Bias is an opinion based on preference, of having experience of two things and preferring one over the other.