Example: Consider the measurement of pressure in a gas through measurement of its temperature and density .
Let the uncertainties in
and be and where is determined from the ideal gas law
.
Hence the uncertainty in
is
Here we have used and . Further
Suppose the uncertainty in is specified as and as at . Note that in the expression above is absolute temprature. Using and is calculated as 0.0119, i.e. .
and density 
.
Let the uncertainties in
and 
where 
is determined from the ideal gas law
.
Hence the uncertainty in
and 
. Further
and 
at 
. Note that 
and 
is calculated as 0.0119, i.e. 
.
