1. Topic: How do we calculate percent deviation?

2. Accepted Value— - Difference— - x 100
Deviation(%) = difference from accepted value
accepted value
x 100
Accepted Value— -
Difference— -

3. Examples
A WHB student incorrectly measures the mass of an M&M as 7.8 grams. The actual mass is 7.2 grams. What is the student’s percent deviation?
Step 1- What is the difference?
= 0.6
Step 2 – Divide difference by accepted value
Step 3 – Multiply by 100 to change answer to a percent
0.08 x 100 = 8.3 %
0.6
= 0.083
7.2

4. Examples
A turtle determines the mass of a rock to be 3.5 grams. If the accepted mass of the rock is 3.1 grams, what is the turtle’s percent deviation?
Step 1- What is the difference?
= 0.4
Step 2 – Divide difference by accepted value
Step 3 – Multiply by 100 to change answer to a percent
.129 x 100 = 12.9 %
0.4
= .129
3.1

5. Examples
Derek Jeter guessed that he would hit 30 homeruns last year. He actually hit 23. Jeter’s percent deviation is approximately?
Step 1- What is the difference?
- = -
Step 2 – Divide difference by accepted value
Step 3 – Multiply by 100 to change answer to a percent
- x - = - -
= - -

6. Final question: The actual volume of a cube is 27 cm3
A student finds length of one side to be 3 cm. What is the percent deviation?