In an experiment to measure the density of iron, the following data was obtained. Book value is 7.86 g/cm3. One of the two sets of data is more precise, while one is more accurate. Which of these two sets has the greater precision and which has the greater accuracy

(a) 7.72, 7.74. 7.73. 7.75, 7.74

(b) 7.86, 7.90, 7.78, 7.93, 7.83

Which is more precise?

Which is more accurate?

(a) is more precise

(b) is more accurate

Explanation:

When a given set of values are precise, this implies that all the values are close to each other but may not be accurate. But a set of values are accurate when they are compared and it can be observed that they are close to a given measured value. So we can infer that the values in option (a) are precise, while that in (b) are accurate when compared with the book value given.

a) is more precise

b) is more accurate

Explanation:

(a) 7.72, 7.74. 7.73. 7.75, 7.74

For this set the average is: (7.72+7.74+7.73+7.75+7.74) / 5=7.736

(b) 7.86, 7.90, 7.78, 7.93, 7.83

For this set the average is: (7.86+7.90+7.78+7.93+7.83) / 5=7.86

Accuracy refers to the closeness of a measured set of measures to a known value. In our case that the book value is 7.86g/cm3

We can see that the set (b) is more accurate.

Precision correspond to the closeness of the measurements to each other.

We can see that the set of measures a) is more precise, they are more close one of the each other than the set b)