Question

2. Exercise #2 gives you practice in working with the idea that bias can (and often does!) occur in sampling.

    Which of the following estimates are likely to be biased? Why? Is the bias positive

or negative? Why? (note: Positive bias means a consistent likelihood of overestimating, negative bias is underestimating).

1. You estimate the average number of bank customers waiting for service whenever the bank is open by counting the number of customers whenever you go to the bank.

2. You estimate the proportion of 7-12 year old children using helmets when they ride bikes by asking parents if their child wears a helmet when the child is brought to the physician’s office for a “well” visit.

3. A highway patrolman parks next to a highway and records speeds on his radar to estimate the percentage of people exceeding the speed limit on that highway

Answer 1