I have a splitting headache…

Completely missed the dartboard!!!

100g

• Refers how close a measurement is to the actual (true) value.

• Dartboard Analogy:

The bull’s eye is the actual point where a person is aiming for.

Accurate

• “correct”. A measurement is considered accurate if correctly reflects the size of the object being measured.

• How close are you to the actual/accepted value?

• Does the practice of using body parts as measurement tools produce accurate results?

• Refers how close a a group of measurements are to one another. (reproducibility)

Person

1

2

3

4

5

Measurement (cm)

1.25

1.26

1.24

1.25

1.26

Precise

• A precise measurement is repeatable and reliable. Getting the same measurement each time.

• Does the practice of using body parts as measurement tools produce precise measurements? (were all of your results the same?)

Accurate or precise?

Accurate and Precise!

Accurate or Precise?

neither

Accurate or Precise?

Precise

• We can never get a perfect measurement, the best that we can do is get as close as possible within the limitations of our measuring instruments.

The line falls between23.1 and 23.2

23.1?

The measurement extends

between 23.1 and 23.2

Therefore, we can be sure the measurement is 23.1?

This is where “estimation” comes into play…

Person

1

2

3

4

5

Measurement (cm)

1.25

1.26

1.24

1.25

1.26

1st two numbers (1.2_) are certain.

Last number is (1.2?) uncertain.

Every measurement

REQUIRES only 1 estimation!!!