Chapter 1 Measurements Accuracy and Precision Timberlake Lecture

Chapter 1 Measurements Accuracy and Precision Timberlake Lecture. PLUS 1

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

Precision How well several measurements agree with each other good precision poor precision Timberlake Lecture. PLUS 3

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 Timberlake Lecture. PLUS 4

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? Timberlake Lecture. PLUS 5

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

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

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

Learning Check AP 1 Match the following terms 1) Accuracy 2) Precision ___ 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? Timberlake Lecture. PLUS 9

Solution AP 1 Match the following terms 1) Accuracy 2) 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. Timberlake value. Lecture. PLUS 10

Learning Check AP 2 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. Timberlake Lecture. PLUS 11

Solution AP 2 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. Timberlake Lecture. PLUS 12

Learning Check AP 3 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 Timberlake Lecture. PLUS 13

Learning Check AP 3 True(1) or false (2). Measurements can have 1 2 1 1 poor accuracy and poor precision good accuracy and poor precision poor accuracy and good precision good accuracy and good precision Timberlake Lecture. PLUS 14