Question

The density of a sample of metal is calculated using these three different sets of data: 2.9 g/mL, 2.8 g/mL, and 3.0 g/mL. If the true density of the metal is 2.1 g/mL, what can be said about these calculated density values?

Answer 1

They are precise but not accurate.

Precision refers to how close your measurements are to each other. Your calculated densities are all within 0.1 g/mL of the average value (2.9 g/mL).

Accuracy refers to how close your measurements are to the known value. Your average density is far from the known value (almost a 40 % error).