Download Accuracy vs. Precision

Accuracy vs. Precision
2 minutes: Write what
you think accuracy and
precision mean
1 minute: discuss at your
table what you think
Definitions:
Accuracy and precision are used in context of
measurement. Accuracy is the degree of
conformity of a measured or calculated
quantity to its actual (true) value, while
precision is the degree to which further
measurements or calculations show the same
or similar results. In other words, the precision
of an experiment/object/value is a measure of
the reliability of the experiment, or how
reproducible the experiment is. The accuracy
of an experiment/object/value is a measure of
how closely the experimental results agree
with a true or accepted value.
1 minute: Do you
need to refine your
definitions?
Chart Comparison:
Accuracy
Precision
Definition
The degree of
closeness to true
value.
The degree to which
an instrument or
process will repeat
the same value.
Measurements
Single factor or
measurement
About
Uses
A term used in
measuring a process
or device.
Physics, chemistry,
engineering,
statistics and so on.
Multiple
measurements or
factors are needed
A term used in
measuring a process
or device.
Physics, chemistry,
engineering,
statistics and so on.
Examples:
• A stopped clock will be accurate twice in
day, but it will not be precise - a
reflection on its quality. If a clock reflects
the right time in 10 readings at 10
different points in time it can be
considered precise and therefore of high
quality.
• So, if you are playing soccer and you
always hit the left goal post instead of
scoring, then you are not accurate, but
you are precise!
More Info:
• Another difference between
the two is that accuracy can be
determined by one
measurement while many
measurements are needed to
determine precision.
In other words….
Accuracy
• Accuracy is how close a measured
value is to the actual (true) value.
Precision
• Precision is how close the measured
values are to each other
Fill in the three
targets on your
paper
How would you classify these?
Low Accuracy
High Precision
High Accuracy
Low Precision
High Accuracy
High Precision
Do your targets match
the ones on the
previous slide?