Question: A research team compared two methods of measuring treadwear on tires. Eleven tires were each measured for treadwear by two different methods: one method was based on weight while the other method was based on groove wear. For convenience, each tire was measured first by weight method and then second by the groove wear.

a. The two samples are which of the following: two independent or two dependent (matched pairs)? Explain.

b. What type of study is found—observational or randomized experiment? Explain.

c. What is the experimental unit?

d. What is the response variable?

e. What is the explanatory variable?