# Percent difference and uncertainty

#### mike2601

1. Homework Statement

How do we solve this problem?

% Difference = (l 0.282 +/- 0.0019 - 0.288 +/- 0.04 l) / 0.285 +/- 0.02

2. Homework Equations

Percent Difference = (l value - average value l) / average value x 100%

3. The Attempt at a Solution

Related Introductory Physics Homework Help News on Phys.org

#### Delphi51

Homework Helper
Welcome to PF, Mike.
You are supposed to show your attempt(s) so we have some idea what method you are supposed to use, and to avoid giving solutions to people who haven't tried the problem on their own.

For the subtraction, I would add the uncertainties.
For the division, I would convert the uncertainties into per cents of the main values, add the per cents, and finally find that % of the main value.

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving