Error bar

Error bars are used on graphs to indicate the error in a reported measurement. They give a general idea of how accurate a measurement is, or conversely, how far from the reported value the true (error free) value might be. Often, but not always, the error bars indicate one standard deviation of uncertainty. They also commonly represent one standard error of the mean.

Error bars can be used to visually compare two quantities, subject to often unstated assumptions, to determine whether differences are statistically significant. They can also show how good a statistical fit the data has to a given function. Scientific papers in the experimental sciences are expected to include error bars on all graphs, though the practice differs somewhat between sciences, and each journal will have its own house style.

External links

• Using Error Bars in your Graph — North Carolina State University