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 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 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 every student versus accuracy thanks for watching this tutorial you