Standard deviation is the most common measure of data variation or spread (OpenStax, 2013). In descriptive statistics, standard deviation is identified by the variance value and used to assess the overall amount of data variation or to evaluate the distance of a particular data point from the mean. A smaller standard deviation indicated a higher level of concentration of values around the mean while a larger one imply a larger distance of values in general to the mean point. With statistics being a highly applicable science, standard deviation as a popular statistical term and measuring instrument is also widely used in different fields to make better conclusions considering data sets.
Recently in environmental science, researchers have been applying standard deviation as a means of check and assessment of carbon dioxide emissions reports, which they named “Control Chart Methodology for Detecting Under-reported Emissions” (EPA, 2015). The purpose of this analysis is to check whether there are monitoring errors causing under-reporting of emissions. The methodology is a compound of control charts, some of the key components of which are upper and lower control limits. Data points are valid if they are located between these two limit lines, whose graphs researchers build by adding or subtracting three standard deviations (or two in case of warning control) to or from the arithmetic average of the daily average carbon dioxide concentrations or the baseline mean. As reports validity follows normal distribution rule, researchers consider them more effective in indicating the emissions level if their values lying closer to the baseline mean.
This method of assessment is showing effectiveness in the quality control of emissions reports and proving to possess advantages that were not performed in the conventional RATAs (relative accuracy test audits) method, which used to be the only way of reports evaluation.
EPA United States Environmental Protection Agency. (2015, March). Control Chart Methodology for Detecting Under-reported Emissions. Retrieved from http://www.epa.gov/airmarkets/documents/monitoring/control-chart.pdf.