hello and welcome to the chemistry
solution this tutorial is on precision
versus accuracy let's get started
accuracy is how close measured values
are to an accepted or correct value
while precision is how close measured
values are to each other
so if we look at this illustration of a
target the X's on the left target are
both accurate and precise they're
accurate because they all hit the bull's
eye of the target and they're precise
because they're all close together
looking at the example on the right the
X's are precise because they're all
close to each other but not accurate
because they miss the bullseye of the
target now let's look at an example
using some real numbers the accepted
value for the density of silver is 10.5
grams per centimeter cubed using the
average values of the three measurements
from each group below which set is more
accurate which data set is more precise
so if we look at the values from Group A
and find the average value we come up
with an average of ten point eight grams
per centimeter cubed if we take the
average value from the measurements of
Group B we come up with a value of
thirteen point two grams per centimeter
cubed the average for Group a ten point
eight grams per centimeter cubed is very
close to the accepted value for the
density of silver of ten point five
grams per centimeter cubed so a group a
has the most accurate data set however
group a's data is not very precise
meaning the measured values vary widely
from each other the average value
derived from group B's data thirteen
point two grams per centimeters cubed is
not very accurate because it deviates
significantly from the accepted value
for the density of silver which is ten
point five grams per centimeters cubed
however group B did have the more
precise data meaning all their
measurements were very close together
hopefully you now have a better
understanding of
versus accuracy thanks for watching this
tutorial
