# Science By Numbers

To be precise or to be accurate now that is the question at hand. What do these two things mean? Lets give a little background first. Significant digits, or sig digs as I like to call them, are numbers that contribute to the precision of a whole number. The Atlantic-Pacific rule, contrary to what you may believe, is not about our major oceans at all!  What this rule states is that if the number has a decimal, you count from the left, or pacific side at the first nonzero number. For example .0010 would have 2 sig digs because you count starting from the one! If there is no decimal place you count from the right (Atlantic) side starting again with the first nonzero number. For example 10 would have one sig dig because the zero doesn’t count! Again, Significant digits all contribute to the precision of a number. What is precision? To be precise is to carry the measurement you are taking to the last possible number. If you have a 3 beam balance that means you have 3 precise measurements, but you always estimate a fourth because its science and science likes to be precise! To be accurate is to have a count of something. If you have 10 m&m’s you do not need to measure this you can simply count it, and that is what accuracy is about. So what? What is the big deal with all these numbers? It doesnt matter! Of course it does! Significant digits is a way of telling how precise your data is. If you have 8 grams of sugar and 8.2 grams of sugar, sure that is not much of a difference. BUT IF you have 1.44 million dollars and you round it to 1 million you are losing 440,000 dollars just because you were not precise enough to put your significant digits. What a waste!!

http://www.docstoc.com/docs/55853155/Accuracy-Precision-and-Significant-Figures-in-Measurement 