1. grams. kilograms Brian estimated the mass of my pet llama to be 95,000 grams. When he placed it on a balance he got a reading of 49 kilograms, what was Brian’s % Error? INTRO QUESTION!!! D=93.9%

2. (%E) PERCENT ERROR (%E) Why do we have percent error? Percent Error A.K.A. Percent Deviation

3. FORMULA % Error % Error = Accepted Value – Measured Value x100 Accepted Value Your answer should always be positive!!! If it is not you did something wrong!

4. EXAMPLE QUESTION: 1. Write out Formula: % Error AV – MV % Error = AV – MV x100 AV EXAMPLE: percent error EXAMPLE: Bob calculated the density of water to be 1.08 g/mL, but water has an actual Density of 1.0 g/mL. Calculate Bob’s percent error. 3. Plug into formula: % Error 1.0 g/mL – 1.08 g/mL % Error = 1.0 g/mL – 1.08 g/mL x100 1.0 g/mL 4. Reduce & Solve: %E.08 %E =.08 x100 1.0 %E = 8% %E = 8% AVMV 2. ID the AV & MV: AV = 1.0g/mL MV =1.08g/mL

5. % Error AV – MV % Error = AV – MV x100 AV

6. % Error Practice # 1 1.15g/mL 1.13 g/mL If Mr. Richards Calculated the density of water to be 1.15g/mL and Galileo calculated the Density of water to be 1.13 g/mL who was more correct? SHOW ALL WORK! Mr. R % E = ____15%______ Galileo %E = _____13%_____ ____________ is more correct! Galileo

7. % Error Practice # 2 A Farmer anticipated his apple orchard to make 15,450 tons of apples, yet the farms final yield was weighed to be only 13,849 tons. What was the farmers percent error ? SHOW ALL WORK! A Farmer anticipated his apple orchard to make 15,450 tons of apples, yet the farms final yield was weighed to be only 13,849 tons. What was the farmers percent error ? SHOW ALL WORK! D = 11.6%

8. YankeesThe Yankees were expected to win 94 games and lose 68 this year. But this year their final record was 104 wins and 58 losses. What is the % % error of their wins wins? More Practice # 3… D = 9.6%