Chapter 5.2, Problem 5.35E

(a)

To determine

To give at least two reasons why the Hunter college study gave such different results.

Answer to Problem 5.35E

Regular does not mean always.

People tend to be more observant at intersections compared to long stretches of road without intersections.

Explanation of Solution

Given:

  $23\%$ of the observed drivers were talking on cell phone

More than $50\%$ of the surveyed people admitted that they regularly talk on cell phones during driving.

First Reason : If somebody regularly talks on the cell phones during driving, then it is most likely that they are not always talk on their cell phones during driving and thus you would have to be lucky to catch them at that precise time. It is probably already surprising that they obtained such a large percentage of $23\%$ .

Second Reason: People tend to be more observant at intersections especially if they have to turn. Since the cell phone reduces your observance, it is the intersection. Moreover they might also hung up before they approach the intersection because they might need both hands to turn.

(b)

To determine

To explain why the percent of drivers talking on cell phones have been about the same as the results from national surveys and why or why not.

Answer to Problem 5.35E

Yes.

Explanation of Solution

Yes, the result would have been about the same because nothing was changed about the sampling method and the sampling method causes the deviation between the result.