Some studies of the relationship between car color and frequency of accidents have found that red cars are more likely to be in
accidents than black cars, despite how visible they are. Some experts warn that we should not conclude red cars are less safe than black cars because of possible confounding. Which of the following best describes what confounding means in this situation? a. lt can be hard to determine whether red cars or black cars are more visible on modern
b. Much of the data on car color and accidents is contradictory, thus making it hard to draw
c. Much of the data on car color and accidents is subject to bias, thus making it hard to draw
d. Studies of this type are all observational, and it is not possible to separate the effect of car color
