Getting Good Data

Quiz on Getting Good Data
1. selection bias-only seniors’ opinion
2. variability-larger sample size could reduce variability, but larger sample does not reduce bias
3. reliability-his guesses are all over the place, not mostly higher or mostly lower
4.GI bad, biased, or unreliable data
GO invalid conclusion
5. no
1. A student wants to gather the school wide opinion of the new all go time all the time schedule. They
decide to poll 200 seniors (30% of the class 7% of total school population) to see if they are or are not in
favor of the new schedule. Would you consider this poll lacking in quality due to bias or variability?
2. The student from the previous question decides to poll 400 seniors instead of 200 seniors. Will this
reduce the variability of the results, the bias of the results, or both?
3. A student thinks he has a special ability to guess someone’s weight by looking at them. I found 5 people
who weigh the same exact amount 145lbs and asked the student how much they weighed. He stated the 5
people weighed 130,155,140,160,145. Does the student have a greater problem with bias or reliability with
his “measurements”?
4. The phrase “garbage in -> garbage out” is used to describe a poorly designed statistical experiment.
What do you think “garbage in” and “garbage out” refer to?
5. An airline once advertised that it had “decreased lost baggage by 100% in the past six months.” Does
this claim make sense?