Measurements Accuracy and Precision Timberlake Lecture PLUS 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. Timberlake Lecture. PLUS 8

Learning Check! 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 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 value. Timberlake Lecture. PLUS 10

Precision and Accuracy Timberlake Lecture. PLUS 11

How Precise Can Our Measurements Be? l You can only be as precise as your ruler or instrument allows you. ¡ Find the interval between the smallest marks on your ruler ¡ Move your decimal place one spot to the left. ¡ This is how precise you can be: estimate the last digit in your measurement and go to that many decimal places in the measurement you record. Timberlake Lecture. PLUS 12