Accuracy and Precision s2

Name ______Hr ______

ACCURACY AND PRECISION

What is the difference? ACCURACY is when your outcomes are close to what you want. For example, if you are looking to hit a bulls-eye on a dart board you will be accurate if you hit the darts in the bulls-eye.

PRECISION is when your outcomes are grouped close together but not close to what you intended to get. For example, if you wanted to hit the bulls-eye but hit all three darts in the 20 instead. You are precise, although not accurate.

Let’s see how each of us shoots, accurately or precisely, neither or both!!!

1.) How many students were accurate in their shots? ______Precise? ______

Neither? ______Both? ______2.) What percentage of students were: (show your work)

Accurate? ______

Precise? ______

Neither? ______

Both? ______

3.) If you were to show the percentage relationships on a pie graph how would it look?

4.) Suppose you need to measure the length of a wire and you have two tape measures. One is marked every 0.001 m, and the other is marked every 0.1 m. Which tape should you use and WHY?

SIGNIFICANT FIGURES are the digits in a measurement that are known with certainty. Usually you can tell how many significant figures a number has just by looking at it. For example, 1.683 has four significant figures because the numbers 1683 are known for sure. The number 1.680 has four significant figures because the last zero does count. If the zero were in front of the decimal point or the non-zero digits, it would NOT count simple because it is a place holder. Examples: 0.034 has two significant figures, 0.45567 has five.

5.) How many significant figures do the following numbers have?

2.34 ______0.006 ______

89,675 ______96.55 ______

450 ______0.09 ______

0.12 ______8.675309 ______