Question

A digital scale reports a 10 kg weight as weighing 8.975 kg. Which of the following is true?

A. The scale is neither precise nor accurate.
B. The scale is accurate but not precise.
C. The scale is both accurate and precise.
D. The scale is precise but not accurate.

Answer 1

Answer: D. The scale is precise but not accurate.

Step-by-step explanation:

Accuracy and precision are two distinct concepts in measurement:

Accuracy refers to how close a measured value is to the true or accepted value.

Precision refers to how close repeated measurements are to each other.

Given that the digital scale reports a 10 kg weight as 8.975 kg, there is a discrepancy between the reported value and the true value. Therefore, the scale is not accurate.

Now, let's consider precision. Precision is about the consistency of measurements. If the scale consistently reports the weight as 8.975 kg when it's actually 10 kg, it is showing a consistent, though imprecise, result.

So, the correct answer is:

D. The scale is precise but not accurate.

Answer 2

Option D is correct; the scale is precise but not accurate, as it consistently reports a measurement that is not close to the true 10 kg weight.

Step-by-step explanation:

The correct answer is option D. The scale is precise but not accurate. Precision refers to how closely repeated measurements are to each other, whereas accuracy pertains to how close a measurement is to its true value. In this case, as the digital scale consistently reports the wrong value (8.975 kg instead of 10 kg), it is not providing accurate measurements.

However, because digital scales can measure the mass of an object up to the nearest thousandth of a gram as seen in many physics labs, we can infer that the scale is likely to be precise in its repeated measurements even though it is not providing the correct weight. Therefore, while the scale shows consistency in the measurements, which demonstrates precision, it still shows a systematic error in indicating the true mass of the weight, indicating a lack of accuracy.