Accuracy and Precision

I cannot explain this without examples, so here is one.

A man is throwing darts at a dart board. All his darts land in a cluster, each dart within a milimeter away from each other, but far away from the bullseye. He is very precise, but not very accurate.

Here is another example: Your scale at home says you weigh 81 pounds. Then you got to a chekc up at the doctor's office and the doctor's scale says you weigh 81.4 pounds. Both scales are accurate, but the doctor's scale is more precise because it can measure more after the decimal point than your scale at home. 81 pounds is still accurate, but 81.4 pounds is more precise. Your scale weighed to the best of its abilities, wich, in this case, has nothing after the decimal point. But if your scale says you weigh 8 pounds, that is not accurate because accuracy comes before the decimal point. Precision comes after the decimal point. 1.000 is not more accurate than 1, but it is more precise because the more digits there are after the decimal point, the more precise that number is.

Confused yet? Oh, and what does this mean for what we told you about pi and using 3.14 to solve problems?

Alana