| ??? 11/25/09 06:21 Read: times |
#171151 - I think you have 'em reversed. Responding to: ???'s previous message |
Justin Fontes said:
A simple example, suppose I throw a couple of darts at a board. I hit the bull's eye once, but I have a lot of scattered hits on the board. Accuracy is that I hit the bull's eye. Now, suppose I throw the darts again, but they all land slightly off from the bull's eye in the SAME place. This represents precision. The great part about precision is that it can be offset so that the darts will hit the bull's eye. This is why precision is more important than accuracy. http://www.tutelman.com/golf/measure/precision.php There's no guarantee I'm right, nor is there one that the golfer is right. The way I learned it is that accuracy is the repeatability of a specific result to within a specified limit (tolerance). Precision is the limit within which any one of the results falls, relative to the objective. Example ... commercial grade crystal oscillators are accurate to within 100 ppm (parts per million). This one here is precisely at 19.999986 MHz according to my 10 ppm counter. It's marked 20.0000 MHz. So its precision is indicated by the xx.0000 while its accuracy is 100 ppm. The precision defines the size of the bullseye, while the accuracy defines the size of the pattern within which they fall. From this I would conclude that a rifle with a good telescopic sight, would allow one firing it from, say, 200 yards, to aim quite precisely at a point that doesn't vary more than a millimeter, but with 1/4-minute accuracy, the group of five shots would have to lie within a circle of about 1/2-inch diameter. Some dictionaries claim the two are synonymous. RE |
