Engr201Lectureweek4

# Engr201Lectureweek4 - ENGR 201 Evaluation Presentation of...

This preview shows pages 1–6. Sign up to view the full content.

1 10/11/2011 ENGR201 Lecture 4 Fall 2011 1 ENGR 201 Evaluation & Presentation of Experimental Data Lecture 4: Uncertainty Analysis Part 1 D. Miller, Mechanical Engineering & Mechanics C. Peters, Electrical & Computer Engineering Drexel University 11 October 2011 10/11/2011 ENGR201 Lecture 4 Fall 2011 2 Announcements 1 Coverage of Written and On-line Midterm this week reading and notes from lecture 1, 2, and 3 Homework problems for lectures 1, 2, and 3 Quizzes for lecture 1, 2 Written test Thursday 10/13/2011 at 8:00-9:00 AM in Main Auditorium (computational problems) Tables will be provided You may have 1 handwritten formula sheet On-line test from 5:00 PM Thursday 10/13 to 5:00 PM Friday 10/14 (concept questions, low computations) There is NO MAKEUP Check Bb Vista later this week for additional details and for those with special arrangements

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 10/11/2011 ENGR201 Lecture 4 Fall 2011 3 Announcements 2 • No Quiz this week • Next week’s quiz will include both lecture 4 and Lecture 5 on Finite Statistics 10/11/2011 ENGR201 Lecture 4 Fall 2011 4 Homework and Readings for Week 4 • Reading from text: – Section 5.1, 5.2, 5.3, 5.4 and 5.5 – make sure to pay attention to examples • Problems from text: – 5.6, 5.8, 5.10
3 10/11/2011 ENGR201 Lecture 4 Fall 2011 5 Measurement Process of assigning a value to a physical quantity Error Difference between our assigned value and the true value Uncertainty Estimate of the probable error in our measurement Errors are a property of the measurement Errors come from instruments, finite statistics, procedures Uncertainty is a property of the result Using uncertainty analysis we will identify, quantify, and combine error estimates to estimate the error in our final result Definition Review 10/11/2011 ENGR201 Lecture 4 Fall 2011 6 Purpose Estimating the ± what? as we design a measurement system Method Introduce uncertainty analysis Why? Develop a methodical approach Make critical evaluations of potential elements of the apparatus Spend your money on components that will really make a difference in reducing the uncertainty This Lecture

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4 10/11/2011 ENGR201 Lecture 4 Fall 2011 7 Repeated Measurements Width of the distribution is a measure of the random error Shifts the center of the distribution from the true value Result of the i-th measurement 10/11/2011 ENGR201 Lecture 4 Fall 2011 8 Total Error Here s what you will report as a result of your measurements We are going to work on how to estimate u x when the experiment (measurement system) is being designed Uncertainty analysis is the method to quantify the u x term %) ( ' P u x x x
5 10/11/2011 ENGR201 Lecture 4 Fall 2011 9 Assumptions for Uncertainty Analysis Test objectives are known & process is clearly defined Known corrections to systematic error have been applied (Set the bathroom scale to zero before getting on) Systematic errors are independent (uncorrelated) of

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 11/11/2011 for the course ENGR 231 taught by Professor Olehtretiak during the Fall '10 term at Drexel.

### Page1 / 27

Engr201Lectureweek4 - ENGR 201 Evaluation Presentation of...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online