What is bias?

Question

I have no idea of this concept in statistics.

All I know is that some samples of a population (say, 50 students in a school, 70 sailors on the Kitty Hawk, or 100 members on a web site) are biased and some (a particular group of people, like skaters, gamers, girls that have gone out with many guys, etc.) are not.

But I do not understand anything about it at all. What is bias, in statistics?

Answer 1

A biased sample is a statistical sample of a population where some members of the population are less likely to be included than others. An extreme form of biased sampling occurs when certain members of the population are totally excluded from the sample (that is, they have zero probability of being selected). For example, a survey of high school students to measure teenage use of illegal drugs will be a biased sample because it does not include home schooled students or dropouts. A sample is also biased if certain members are underrepresented or overrepresented relative to others in the population. For example, a "man on the street" interview which selects people who walk by a certain location is going to have an over-representation of healthy individuals who are more likely to be out of the home than individuals with a chronic illness.

A biased sample causes problems because any statistic computed from that sample has the potential to be consistently erroneous. The bias can lead to an over- or under-representation of the corresponding parameter in the population. Almost every sample in practice is biased because it is practically impossible to ensure a perfectly random sample. If the degree of underrepresentation is small, the sample can be treated as a reasonable approximation to a random sample. Also, if the group that is underrepresented does not differ markedly from the other groups in the quantity being measured, then a random sample can still be a reasonable approximation.

Answer 2

bias in science is when you only write down what you want to and not paying attention to the other data in the experiment so you get a bias experiment or conclusion

Answer 3

biased is like when you r surveying a certain group on a question like who is the best band and of course its going to lead to one certain band. unbiased is like you r asking every 5th person that walks into the mall and ask that question chances r the answers will vary

Answer 4

Listen, there are many men out there. You just gotta look. I had a hard time too, but it's worth it when you find the right person. M'kay? Hang in there.