# accuracy and precision

## accuracy

The accuracy of a measurement is how close the measurement is to the true value. If you were to hit four different golf balls toward an over-sized hole, all of them might land in the hole. These shots would all be accurate because they all landed in the hole. This is illustrated in the sketch below.

## precision

As you can see from the sketch above, the four golf balls did not land as close to one another as they could have. Each one landed in a different part of the hole. Therefore, these shots are not very precise. The precision of measurements is how close they are to each other. If you make the same measurement twice, the answers are precise if they are the same or at least very close to one another. The golf balls in the sketch below landed quite close together in a cluster, so they would be considered precise. However, they are all far from the hole, so they are not accurate. Q: If you were to hit four golf balls toward a hole and your shots were both accurate and precise, where would the balls land? A: All four golf balls would land in the hole (accurate) and also very close to one another (precise).

## instructional diagrams

No diagram descriptions associated with this lesson

## questions

if a measurement is precise, it must also be accurate.

``````a. true

-->  b. false
``````

only accurate measurements are precise.

``````a. true

-->  b. false
``````

which set of measurements best represents precision if the true value is 6.80 kg?

``````a) 6.80 kg, 6.70 kg, and 6.90 kg

b) 6.75 kg, 6.80 kg, and 6.85 kg

c) 5.80 kg, 6.80 kg, and 7.80 kg

-->  d) 6.10 kg, 5.99 kg, and 6.11 kg
``````

which set of measurements best represents accuracy if the true value is 6.80 kg?

``````a) 6.80 kg, 6.70 kg, and 6.90 kg

-->  b) 6.75 kg, 6.80 kg, and 6.85 kg

c) 5.80 kg, 6.80 kg, and 7.80 kg

d) 6.10 kg, 5.99 kg, and 6.11 kg
``````

## diagram questions

No diagram questions associated with this lesson