Accuracy describes the correlation between the measured value and the accepted v

Question

Accuracy describes the correlation between the measured value and the accepted value. The accuracy of a measurement, or set of measurements, can be expressed in terms of error: error = (average measurement) - (accepted value) The larger the error is, the less accurate is the measurement. Precision describes the reproducibility of a measurement. To evaluate the precision of a set of measurements, start by finding the deviation of each individual measurement in the set from the average of all the measurements in the set: deviation = |(individual measurement) - (average measurement)| Note that deviation is always positive because the vertical lines in the formula represent absolute value. The average of all the deviations in the set is called the average deviation. The larger the average deviation is, the less precise is the data set. In a laboratory experiment, the density of a concentrated sugar solution was determined by measuring the volume of the solution and corresponding mass. Three students each made a set of measurements using a different balance and used the results to calculate density. Their results are summarized here. Rank the data sets in decreasing order of precision. Rank from most to least precise. To rank items as equivalent, overlap them. he correct ranking cannot be determined. The accepted density of the sugar solution is 1.390g/mL . Based on the average value of each data set, rank the data sets in decreasing order of accuracy. Rank from most to least accurate. To rank items as equivalent, overlap them. The correct ranking cannot be determined.

Explanation / Answer

Upon calculation one obtains
set average density(g/ml) average deviation(g/ml)
1 1.385 0.010

2 1.414 0.045

3 1.406 0.210

* Numbers are rounded up to third decimal place

a. In decreasing iorder of precission

Set 1 > set 2 > set 3

b. In deacring order of accuracy(determined by substracting average density from 1.390 g/ml)

Set 1 > set 3 > set 2

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.