To calculate relative error, you must first calculate absolute error. Absolute error is the quantitative amount of incorrectness between an estimate and the actual value of a measurement, while relative error is a comparison between the absolute error and the total size of the measured item.
To calculate absolute error, subtract the experimental value, or estimate, from the actual value, and discard the negative sign, if applicable. To calculate relative error, divide the new number, the absolute error, by the real value. Because relative error is most often designated as a percentage, multiply this quotient by 100 to complete the calculation.
For example, to calculate the relative error of the distance from one tree to another, a person could pace off the steps in between the two trees and guess that the distance is 22 feet. If the actual distance between the trees is determined to be 21 feet 9 inches, the absolute error is 3 inches, or 0.25 feet. To calculate the relative error, divide 0.25 feet by the actual value, 22 feet, to get 0.01136. Multiply that number by 100 to determine the relative error, in percentage form, is 1.14 percent. This is a very low relative error.
Learn MoreErrors in the chemistry lab can arise from human error, equipment limitations and observation errors. Some other sources of errors include measurement values that are not well defined and inconsistent experiment techniques.
Full Answer >Specific gravity, also known as the relative density, is calculated by dividing the density of a substance by a reference density. The most common reference density is pure water, making one common definition of specific gravity the ratio of a substance's density to that of pure water.
Full Answer >Cumulative relative frequency is a statistical calculation figured by adding together previously tabulated relative frequencies that makes a running total along a frequency table, according to Connexions. For instance, the first relative frequency of an occurrence is two out of 20 and the second relative frequency is five out of 20. The two frequencies are added together to make seven of 20, or 0.35 for a cumulative relative frequency.
Full Answer >To calculate the percentage of error, subtract the experimental value from the exact value, divide the difference by the exact value and multiply the final answer by 100 percent. You need to know the experimental value and the exact value to complete this task.
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