Final answer:
Set D, with measurements of 8.4, 8.3, 8.5, and 8.6, is the most precise and accurate in comparison to the accepted value of 8.4. It exhibits the least variation among measurements and is closest to the accepted value.
Step-by-step explanation:
The question asks which set of data is most precise when compared to an accepted value of 8.4. Precision refers to how closely individual measurements agree with each other, while accuracy refers to how close measurements are to the accepted value. To determine precision, we look at the consistency of measurements within each set of data.
Student A's values: 14.0, 14.5, 13.8, 13.9 are not very precise because they have more variation among them. Student B's values: 12.0, 12.1, 12.0, 12.0 are precise because they are very close to each other. Student C's values: 7.6, 7.7, 7.8, 7.9 show a consistent increment and are also precise. Lastly, Student D's values: 8.4, 8.3, 8.5, 8.6 are precise and accurate because they not only have small variations among them but also are very close to the accepted value of 8.4.
Therefore, set D is the most precise and accurate, followed by set C for precision, but set C is slightly less accurate than set D as it is just under the accepted value. Set B is also precise but not as accurate as set C or D. Set A is the least precise and least accurate among the four.