Medeiros, Pledson Guedes deSampaio, Elvis dos Santos2015-03-032015-02-262015-03-032012-07-20SAMPAIO, Elvis dos Santos. Grafico misto de controle da media com amostragem em dois estagios. 2012. 82 f. Dissertação (Mestrado em Probabilidade e Estatística; Modelagem Matemática) - Universidade Federal do Rio Grande do Norte, Natal, 2012.https://repositorio.ufrn.br/jspui/handle/123456789/18642This paper proposes a new control chart to monitor a process mean employing a combined npx-X control chart. Basically the procedure consists of splitting the sample of size n into two sub-samples n1 and n2 determined by an optimization search. The sampling occur in two-stages. In the first stage the units of the sub-sample n1 are evaluated by attributes and plotted in npx control chart. If this chart signs then units of second sub-sample are measured and the monitored statistic plotted in X control chart (second stage). If both control charts sign then the process is stopped for adjustment. The possibility of non-inspection in all n items may promote a reduction not only in the cost but also the time spent to examine the sampled items. Performances of the current proposal, individual X and npx control charts are compared. In this study the proposed procedure presents many competitive options for the X control chart for a sample size n and a shift from the target mean. The average time to sign (ATS) of the current proposal lower than the values calculated from an individual X control chart points out that the combined control chart is an efficient tool in monitoring process mean.application/pdfAcesso AbertoMonitoramento de processosGráficos de controleGráficos X-barra e npxJunção de gráficos de controleGráfico combinadomasterThesisCNPQ::CIENCIAS EXATAS E DA TERRA::MATEMATICA::MATEMATICA APLICADA