Question

Question 15 of 22 > A Los Angeles Times article reported that the artery walls of people living within 100 meters of a highway thicken more than twice as fast as the average person's. Researchers used ultrasound to measure the carotid artery wall thickness of 1483 people living near freeways in the Los Angeles area. The artery wall thickness among those living within 100 meters of a highway increased by 5.5 micrometers (roughly 1/20th the thickness of a human hair) each year during the three-year study, which is more than twice the progression observed in participants who did not live within this distance of a highway. (a) The study compared artery thickening of subjects in the study who were living within 100 meters of a highway with those who were not. Without reading any further details of this study, how do you know that this was an observational study? The study does not give enough information to suggest this was an observational study. The researchers need to describe whether the participants were randomly selected. None of the choices are correct. This is actually an experiment because the researchers are doing a comparison between individuals who live near highways with those who do not live within 100 meters of a highway. O In an observational study, we simply observe subjects who live near highways and compare them with others who do not live near highways. In an experiment, we would assign where the subjects live. (b) Suggest some variables that might differ between the subjects in the study living within 100 meters of a highway and those who were farther away. Are any of these possible confounding variables? (Think about whether living very close to a highway is a desirable neighborhood.) O Money is a possible confounding variable because those who live near highways might have less money for health Question Source: Moore, The Basic Practice of Statistics, Be Publishen W. Free

Answer 1

Answer:

a)

Option D

b)

Option D

c)

Option D

Because randomized comparative experiment is used when we apply treatment or control the experiment, but in this case there are no treatment or control given by researcher.

Therefore, we can not conduct this study as a randomized comparative experiment as it is not designed experiment, but only an observational study.