The main aim is to perform a detailed statistical analysis of the radioxenon atmospheric background and of the radioxenon “Abnormal Concentrations”, measured at some IMS stations. A descriptive statistical analysis of the empirical distribution was performed and two types of “Control Charts” from the “Statistical Process Control” method, were applied to the measured values, for each IMS station considered. The “Shewhart Control Chart”, sensitive to large variations and the “Exponentially Weighted Moving Average (EWMA) Control Chart”, sensitive to small variations, were used to analyze the overall chronology of the observations and to identify and study those values that significantly deviate from the average value. The “Control Charts” method was then compared with the “Inter-Quartile Range” method currently used by the IDC. The results show that the “Shewhart Control Chart” is particularly meaningful for the periodic monitoring of IMS stations in order to identify large variations of radioxenon activity concentrations, while the “EWMA Control Chart” is more suitable for specific studies on the atmospheric background and on the "anomalies" of radioxenon activity concentrations. The use of “Control Charts” method as a possible complement to the “Inter-Quartile Range” method, could be further investigated.
Statistical Study of the Radioxenon Atmospheric Background and of the Radioxenon Anomalous Values at Some IMS Stations
M. Scagliarini;
2019
Abstract
The main aim is to perform a detailed statistical analysis of the radioxenon atmospheric background and of the radioxenon “Abnormal Concentrations”, measured at some IMS stations. A descriptive statistical analysis of the empirical distribution was performed and two types of “Control Charts” from the “Statistical Process Control” method, were applied to the measured values, for each IMS station considered. The “Shewhart Control Chart”, sensitive to large variations and the “Exponentially Weighted Moving Average (EWMA) Control Chart”, sensitive to small variations, were used to analyze the overall chronology of the observations and to identify and study those values that significantly deviate from the average value. The “Control Charts” method was then compared with the “Inter-Quartile Range” method currently used by the IDC. The results show that the “Shewhart Control Chart” is particularly meaningful for the periodic monitoring of IMS stations in order to identify large variations of radioxenon activity concentrations, while the “EWMA Control Chart” is more suitable for specific studies on the atmospheric background and on the "anomalies" of radioxenon activity concentrations. The use of “Control Charts” method as a possible complement to the “Inter-Quartile Range” method, could be further investigated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
