Eficiência dos gráficos de controle na garantia da validade dos resultados de medição

Abstract

The ISO/IEC 17025 has been applied in laboratories of different areas that seek reliable and traceable results. These laboratories are always looking for statistical techniques to ensuring the validity of their results and often use the control charts to perform the monitoring of their measurement process. In this study pipettes, micropipette, digital power meter (WT 1600) and power quality recorder (Fluke 1760) of three laboratories at a Federal Institution of High Education were chosen to be analyzed. The objective of this study is to identify the most appropriated control chart for monitoring trends between the Shewhart, CUSUM and EWMA. Minitab Statistical Software 18 was used for the control charts construction. This study showed the EWMA control chart as the best alternative to be used for monitoring trends in micropipette. However, for the digital power meter WT 1600 and power quality recorder Fluke 1760 It is suggested that other statistical techniques are tested because application of control chart was not adequate for the type of data that the equipment produces. For the pipettes the control limits were not established.