Online polls In June $2008$, Parade magazine posed the following question: “Should drivers be banned from using all cell phones?” Readers were encouraged to vote online at parade.com. The $July13,2008$ issue of Parade reported the results: $2407(85\%)$ said “Yes” and $410(15\%)$ said “No.”

(a) What type of sample did the Parade survey obtain?

(b) Explain why this sampling method is biased. Is $85\%$ probably higher or lower than the true percent of all adults who believe that cell phone use while

driving should be banned? Why?

We must explain why even a large sample of mall consumers polled by a mall interviewer would not offer a reliable estimate of the current unemployment rate.

A simple random sample (SRS) of size $n$ is made up of $n$ people chosen from the population with an equal chance of being the sample that is actually chosen.

This is an online poll in which readers decide whether or not to vote. As a result, it is a self-selected response sample. People decide whether or not to participate in an involuntary response sample in response to an open offer.

It is slanted toward readers who feel strongly about the issue because it is a volunteer response sample. Involuntary response samples, in which participants choose whether or not to participate in response to an open request, are virtually always biased. Voluntary response samples draw people who are passionate about the topic, resulting in bias. As a result, 85 percent is likely to be greater than the genuine figure since readers who are most passionate about this problem are more likely to have been involved in an accident caused by cell phone use while driving.