2.1.4 Precision and Accuracy

Question 1

Define precision.

Answer 1

The degree to which repeated values, collected under the same conditions in an experiment, show the same results. How close arrows on a target are to each other. The smaller the spread, or range, the higher the precision.

Question 2

Define accuracy.

Answer 2

The degree to which a value obtained by an experiment is close to the actual or true value. How close the arrows are to the centre of the target. An experiment is accurate if the quantity being measured is very close to the commonly accepted value.

Question 3

Define resolution.

Answer 3

The smallest change in a quantity that an instrument can measure. If the smallest value that a piece of equipment can measure is small, resolution is high.

Question 4

Give an accurate, but imprecise value of g.

Answer 4

9.8+/-1.5ms^-2

Question 5

Give an inaccurate, but precise value of g.

Answer 5

8,80+/-0.05ms^-2

Question 6

How does systematic error effect error and precision?

Answer 6

Accuracy is affected, precision is not - as all of the results are just shifted upwards or downwards, the differences between them don’t change; just how close they are to the true value does.

Question 7

How does random error affect accuracy and precision? How can this be overcome?

Answer 7

Affecting both accuracy and precision, random errors can be overcome by creating a mean and repeating results.