1 UNIT ONE Topic: Accuracy and Precision

2 Accuracy How close a measurement is to the actual or true value good accuracy true value poor accuracy true value

3 Precision How well several measurements agree with each other good precision poor precision

4 Accuracy and Precision What can you say about the accuracy and precision in each of the following: Good precision, poor accuracy Good precision, good accuracy

5 In your new job, you are to make the pizzas the size shown above. Your first four pizzas are shown below. What can you say about the accuracy and precision of your pizzas?

6 What can you say about the accuracy and precision of the next four pizzas? The next four pizzas.

7 Accuracy is improving. The two pizzas in the center show good accuracy. However, the precision is poor.

8 Pizza Precision You have very good precision, but poor accuracy. I think the customers will want the pizzas made larger.

9 Match the following terms 1) Precision2) Accuracy ___ How close a measurement is to the true value. ___ How close several measurements are to each other. Can you have data that are precise, but not accurate? Why or why not? Learning Check AP1

10 Match the following terms 1) Accuracy2) Precision _1_ Is how close a measurement is to the true value. _2_ Is how close several measurements are to each other. Yes. Data can be precise, but not come close to the true value. Solution AP1

11 Learning Check AP2 How will each of the following affect accuracy and precision? 1. A meter stick that is missing the first centimeter. 2. A scale that has a zero point that is really five pounds above zero.

12 Solution AP2 How will each of the following affect accuracy and precision? 1. The shortened meter stick will produce measurements that have poor accuracy, but good precision is possible. 2. The poorly calibrated scale will give a weight that is not accurate, but good precision is possible.

13 Learning Check AP3 True(1) or false (2). Measurements can have poor accuracy and poor precision good accuracy and poor precision poor accuracy and good precision good accuracy and good precision

14 Learning Check AP3 True(1) or false (2). Measurements can have poor accuracy and poor precision good accuracy and poor precision poor accuracy and good precision good accuracy and good precision