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If researchers repeatedly observe and quantify a particular biological phenomenon, the measurements will rarely be identical. Part of the variability is due to an inherent variation in biological material being measured. One characteristic of a set of observations measured on a quantitative variable is known as measures of dispersion. There are a number of measures of dispersion of the data, each of which has different attributes. When reporting data in biological research papers, authors often use descriptive statistical methods to describe their study sample. Authors often use the standard deviation (SD) and standard error (SE) to describe the variability of their sample. However, the two are frequently confused with the consequence that the wrong measure is used to describe the variability of interest; may lead to a misinterpretation of the data. Whereas the SD is a measure of the scatter of the observations, the SE is a measure of the precision of the sample mean as an estimate of the population mean. In addition to the SD and SE, coefficient of variation (CV) is also described in this paper.
Keywords: biology; statistic; dispersion; standard deviation; standard error
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