Percent Difference Percent Error
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a percentage of one (or both) values Use Percentage Change when comparing an Old Value to a New Value Use Percentage Error when comparing an Approximate Value to an Exact Value Use Percentage Difference when percent difference formula both values mean the same kind of thing (one value is not obviously
Percent Difference Chemistry
older or better than the other). (Refer to those links for more details) How to Calculate Step 1: Subtract one value
Percent Difference Definition
from the other Step 2: Then divide by ... what? Percentage Change: Divide by the Old Value Percentage Error: Divide by the Exact Value Percentage Difference: Divide by the Average of The Two Values
Percent Difference Physics Lab
Step 3: Is the answer negative? Percentage Change: a positive value is an increase, a negative value is a decrease. Percentage Error: ignore a minus sign (just leave it off), unless you want to know if the error is under or over the exact value Percentage Difference: ignore a minus sign, because neither value is more important, so being "above" or "below" does not make sense. Step 4: Convert percent difference excel this into a percentage (multiply by 100 and add a % sign) The Formulas (Note: the "|" symbols mean absolute value, so negatives become positive.) Percent Change = New Value - Old Value × 100% |Old Value| Example: There were 200 customers yesterday, and 240 today: 240 - 200 × 100% = (40/200) × 100% = 20% |200| A 20% increase. Percent Error = |Approximate Value - Exact Value| × 100% |Exact Value| Example: I thought 70 people would turn up to the concert, but in fact 80 did! |70 - 80| × 100% = (10/80) × 100% = 12.5% |80| I was in error by 12.5% (Without using the absolute value, the error is -12.5%, meaning I under-estimated the value) Percentage Difference = | First Value - Second Value | × 100% (First Value + Second Value)/2 Example: "Best Shoes" gets 200 customers, and "Cheap Shoes" gets 240 customers: | 240 - 200 | × 100% = |40/220| × 100% = 18.18...% (200+240)/2 Percentage Difference Percentage Error Percentage Change Percentage Index Search :: Index :: About :: Contact :: Contribute :: Cite This Page :
using a different procedure to check for consistency. Comparing an experimental relative percent difference value to a theoretical value Percent error is used how can accuracy of a measurement be increased when comparing an experimental result E with a theoretical value T that is accepted percent change as the "correct" value. ( 1 ) percent error = | T − E |T × 100% For example, if you are comparing your http://www.mathsisfun.com/data/percentage-difference-vs-error.html measured value of 10.2 m/s2 with the accepted value of 9.8 m/s2 for the acceleration due to gravity g, the percent error would be ( 2 ) percent error = | 9.81 − 10.2 |9.81 × 100% = 4% Often, fractional or relative uncertainty is used to http://www.webassign.net/labsgraceperiod/ncsulcpmech2/appendices/appendixB/appendixB.html quantitatively express the precision of a measurement. ( 3 ) percent uncertainty = errorE × 100% The percent uncertainty in this case would be ( 4 ) percent uncertainty = 0.0410.2 × 100% = 0.39% Comparing two experimental values Percent difference is used when comparing two experimental results E1 and E2 that were obtained using two different methods. ( 5 ) percent difference = | E1 − E2 |E1 + E22 × 100% Suppose you obtained a value of 9.95 m/s2 for g from a second experiment. To compare this with the result of 10.2 m/s2 from the first experiment, you would calculate the percent difference to be ( 6 ) percent difference = | 9.95 − 10.2 |9.95 + 10.22 × 100% = 2.5% Copyright © 2010 Advanced Instructional Systems, Inc. and North Carolina State University. | Credits
as the value of p https://answers.yahoo.com/question/?qid=20070909073737AAZvDbf or the acceleration due to earth's gravity, g. Since these quantities have accepted or true values, we can calculate the percent error between our measurement percent difference of the value and the accepted value with the formula Sometimes, we will compare the results of two measurements of the same quantity. For instance, we may use two different methods to determine percent difference percent the speed of a rolling body. In this case, since there is not one accepted value for the speed of a rolling body, we will use the percent difference to determine the similarity of the measurements. This is found by dividing the absolute difference of the two measured values by their average, or Physics Lab Tutorials If you have a question or comment, send an e-mail to Lab Coordinator: Jerry Hester Copyright © 2006. Clemson University. All Rights Reserved. Photo's Courtesy Corel Draw. Last Modified on 01/27/2006 14:25:18.
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