1 00:00:00,000 --> 00:00:04,000 When we calculate error with multiple measurements, we're focused on precision. 2 00:00:04,000 --> 00:00:08,000 Let's talk about what precision is. Let's say this is you. 3 00:00:08,000 --> 00:00:11,000 You're a pretty tall person, you know you are about 2 m tall but you're really curious 4 00:00:11,000 --> 00:00:15,000 about exactly how tall you are, so you ask your doctor, Doctor, how tall am I?" 5 00:00:15,000 --> 00:00:20,000 She says, "Well, your height is 2.00 meters. You can trust me; I'm a doctor." 6 00:00:20,000 --> 00:00:25,000 "Okay," you say, "Can you do that measurement again just so I can feel confident about the measurement?" 7 00:00:25,000 --> 00:00:31,000 "Sure, no problem." She does the measurement again. She finds, "Well, you have a height of 1.20 meters. 8 00:00:31,000 --> 00:00:34,000 "I did the measurement and I'm a doctor. You can trust me. " 9 00:00:34,000 --> 00:00:36,000 You're a little confused so you say, "Well, why don't you make that 10 00:00:36,000 --> 00:00:38,000 measurement again, I just want to be sure." 11 00:00:38,000 --> 00:00:41,000 "Well, I did the measurement a third time like you asked, and I've found your height. 12 00:00:41,000 --> 00:00:45,000 It is 2.80 meters.You could trust me. I am a doctor." 13 00:00:45,000 --> 99:59:59,999 Now my question--do you trust your doctor?