National University
CAHINORC - INORGANIC AND ORGANIC CHEMISTRY [LEC]
NUR255
Name: Zardy Gabriel N. Andaya
CORNELL NOTES 1.2
LEARNING OBJECTIVES Notes
Differentiate accuracy and
precision.
Enumerate the measurement
units in common use
Convert measurements done
using the related units into metric
ACCURACY AND PRECISION
system
Accuracy
‒ Refers to HOW CLOSE a
measurement is TO THE
What is Accuracy?
CORRECT VALUE for that
measurement.
Precision
‒ Refers to HOW CLOSE the
agreement is BETWEEN
What is Precision?
REPEATED MEASUREMENTS,
which are repeated under
the same conditions.
The difference between
Accuracy and Precision is that
Accuracy answers the question
What is the difference between “how close?” While, Precision
Accuracy and Precision? answers the question “how
close are they to each other?”
REFLECTION
Accuracy refers to how close a measurement is to the correct value,
while Precision refers to how close that measurement between
repeated measurements.
, Can something be precise but not Because of this, measurements can
accurate? be both accurate and precise,
accurate but not precise, precise
but not accurate, or even neither
precise nor accurate.
For example, imagine a bullseye,
What is an example of accuracy where the hits are close to the
without precision? center, but none are close to each
other; This is an example of
ACCURACY WITHOUT PRECISION.
Imagine the same exact bullseye
where the hits are close to each,
What is an example of precision but are far to the center; This is an
without accuracy? example of PRECISION WITHOUT
ACCURACY.
Imagine the same exact bullseye
where the hits are all in the center
What is an example of accuracy and are all close to each other;
and precision? This is an example of ACCURACY
AND PRECISION.
Imagine the same exact bullseye
What is not an example of where the hits are not close to
accuracy and precision? each other and are far to the
center; This is an example of NOT
ACCURACY AND PRECISION.
Because of this,
Accuracy is the computed
What is Accuracy in simpler
value nearest to the real
terms?
value.
Precision is the closeness of
What is Precision in simpler
the value.
terms?
REFLECTION
Measurements can be both accurate and precise, accurate but not
precise, precise but not accurate, or even neither precise nor accurate.
, What are the two types of There are two types of Precision:
Precision? REPEATABILITY AND
REPRODUCIBILITY.
What is Repeatability? Repeatability
‒ The variations arising when
all efforts are made TO KEEP
CONDITIONS CONSTANT by
using the same instrument
and operator, and repeating
the measurements during a
short time period.
What is Reproducibility? Reproducibility
‒ The variations arising using
the SAME MEASUREMENT
PROCESS among different
instruments and operators,
and over longer time
periods.
What are Errors? Errors
‒ Refers to the disagreement
between the true value.
(e.g., margin of error)
The more measurements
What happens when many (REPLICATES) that are taken or
measurements were used to used to ensure the measurement
measure an object or thing? is right, the closer we can get to
knowing a quantity’s TRUE OR
ACCEPTED VALUE.
If we have the true value, what With this, we can judge the
can we do with it? precision of the results.
What are the two types of There are two types of Errors:
Errors? HUMAN AND TECHNICAL
ERRORS.
REFLECTION
Repeatability is when variations arise to keep conditions constant by
using the same instrument for a short time, while Reproducibility is
when the variations arise using the same measurement process over
long periods of time.
CAHINORC - INORGANIC AND ORGANIC CHEMISTRY [LEC]
NUR255
Name: Zardy Gabriel N. Andaya
CORNELL NOTES 1.2
LEARNING OBJECTIVES Notes
Differentiate accuracy and
precision.
Enumerate the measurement
units in common use
Convert measurements done
using the related units into metric
ACCURACY AND PRECISION
system
Accuracy
‒ Refers to HOW CLOSE a
measurement is TO THE
What is Accuracy?
CORRECT VALUE for that
measurement.
Precision
‒ Refers to HOW CLOSE the
agreement is BETWEEN
What is Precision?
REPEATED MEASUREMENTS,
which are repeated under
the same conditions.
The difference between
Accuracy and Precision is that
Accuracy answers the question
What is the difference between “how close?” While, Precision
Accuracy and Precision? answers the question “how
close are they to each other?”
REFLECTION
Accuracy refers to how close a measurement is to the correct value,
while Precision refers to how close that measurement between
repeated measurements.
, Can something be precise but not Because of this, measurements can
accurate? be both accurate and precise,
accurate but not precise, precise
but not accurate, or even neither
precise nor accurate.
For example, imagine a bullseye,
What is an example of accuracy where the hits are close to the
without precision? center, but none are close to each
other; This is an example of
ACCURACY WITHOUT PRECISION.
Imagine the same exact bullseye
where the hits are close to each,
What is an example of precision but are far to the center; This is an
without accuracy? example of PRECISION WITHOUT
ACCURACY.
Imagine the same exact bullseye
where the hits are all in the center
What is an example of accuracy and are all close to each other;
and precision? This is an example of ACCURACY
AND PRECISION.
Imagine the same exact bullseye
What is not an example of where the hits are not close to
accuracy and precision? each other and are far to the
center; This is an example of NOT
ACCURACY AND PRECISION.
Because of this,
Accuracy is the computed
What is Accuracy in simpler
value nearest to the real
terms?
value.
Precision is the closeness of
What is Precision in simpler
the value.
terms?
REFLECTION
Measurements can be both accurate and precise, accurate but not
precise, precise but not accurate, or even neither precise nor accurate.
, What are the two types of There are two types of Precision:
Precision? REPEATABILITY AND
REPRODUCIBILITY.
What is Repeatability? Repeatability
‒ The variations arising when
all efforts are made TO KEEP
CONDITIONS CONSTANT by
using the same instrument
and operator, and repeating
the measurements during a
short time period.
What is Reproducibility? Reproducibility
‒ The variations arising using
the SAME MEASUREMENT
PROCESS among different
instruments and operators,
and over longer time
periods.
What are Errors? Errors
‒ Refers to the disagreement
between the true value.
(e.g., margin of error)
The more measurements
What happens when many (REPLICATES) that are taken or
measurements were used to used to ensure the measurement
measure an object or thing? is right, the closer we can get to
knowing a quantity’s TRUE OR
ACCEPTED VALUE.
If we have the true value, what With this, we can judge the
can we do with it? precision of the results.
What are the two types of There are two types of Errors:
Errors? HUMAN AND TECHNICAL
ERRORS.
REFLECTION
Repeatability is when variations arise to keep conditions constant by
using the same instrument for a short time, while Reproducibility is
when the variations arise using the same measurement process over
long periods of time.
