Alaboratory instructor gives a sample of amino acid powder to each of four students, i, ii, iii, and iv, and they weigh the samples. the true value is 8.72 g. their results for three trials are student i: 8.72g, 8.74g, 8.70g student ii: 8.56g, 8.77g, 8.83g student iii: 8.50g, 8.48g, 8.51g student iv: 8.41g, 8.72g 8.55g which set of data is both most accurate and most precise?

Let us differentiate accuracy from precision. Accuracy is the nearness of the measured value to the true or exact value. On the other hand, precision is the nearness of the measured values between each other. So, for precision, select the student in which the measured values are very near to each other. That would be Student III. Now, for accuracy, let's find the average for each student.

Student I: (8.72g+8.74g+8.70g)/3 = 8.72 g
Student II: (8.56g+8.77g+8.83g)/3 = 8.72 g
Student III: (8.50g+8.48g+8.51g)/3 = 8.50 g
Student IV: (8.41g+8.72g+8.55g)/3 = 8.56 g

From the given results, the accurate one would be Students I and II. So, we make a compromise. Even though Student III is precise, it is not accurate. If you compare between Students I and II, the more precise data would be Student I. Therefore, the answer is Student I.