WAAP - topic 1 Flashcards
accuracy
judged to be close to the true value
can be affected by random or systematic error
How close the points are to the best fit line
precision
denoting to closeness between results obtained by repeat measurements (consistency). random error could interfere but standard deviation can be used to express this numerically
uncertainty
the interval within which the true value can be considered to lie with a given level of confidence or probability
error
the difference between the measurement result and the true value (if known)
validity
a measurement is valid if it measures what it is supposed to be measuring- UNCERTAINTY GREATER THAN ERROR
true value
the value that would’ve been obtained in an ideal measurement
repeatability
The precision obtained when measurement results are obtained by a single operator using a single method over a short timescale.
reproducibility
The precision obtained when measurement results are obtained. by different operators using different pieces of apparatus.
resolution
The smallest measuring interval and the source of uncertainty in a single reading.
sf and dp
We determine the number of decimal places in a measurement from the resolution of the instrument. Significant figures rules are applied to processed data.
mnemonic for SI base units
m(a)lt cat
what does mlt cat stand for
mass, length, temperature, current, amount of substance (moles), time
units for mltcat
mass - Kg
length - m
temperature - K
current - A
amount of substance - mol
time - s
random error
varying measurements due to unpredictable circumstances. cannot be corrected, can be mitigated by repeat measurements and a mean
systematic error
measurements differing from the true value by a consistent amount each time. can be corrected by using different techniques to take measurements or calibrating the equipment (ensuring it is zeroed).
