Use the following information to answer questions (5) - (7). A tire manufacturer has made some
modifications to its most popular tire and wants to see if the tread on the modified tire will last
longer than the original tire. Because there is much variation in the way people drive, the
manufacturer decides to use blocking to reduce this variation. Twenty cars will be used to test the
tires. Ten cars are randomly selected to receive an original tire on the right rear wheel and a
modified tire on the left rear wheel. The remaining ten cars will receive an original tire on the left
rear wheel and a modified tire on the right rear wheel. Each car will then be driven 10,000 miles and
the amount of wear recorded for each wheel.
-Is this a correct use of blocking?
A)Yes
B)No

Question

Quizplus · Accepted Answer

Blocking is used to reduce variation from extraneous factors, in this case, the variation in driving habits. By using each car to test both the original and modified tires, the experiment controls for differences in driving style, road conditions, and car type, which are all blocked by using the same car for both types of tires. This is a correct application of blocking.

Use the Following Information to Answer Questions (5) - (7)