Tham khảo tài liệu 'engineering statistics handbook episode 2 part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Graphical Output and Interpretation data in the first and last thirds was collected in winter while the more stable middle third was collected in the summer. The seasonal effect was determined to be caused by the amount of humidity affecting the measurement equipment. In this case the solution was to modify the test equipment to be less sensitive to enviromental factors. Simple graphical techniques can be quite effective in revealing unexpected results in the data. When this occurs it is important to investigate whether the unexpected result is due to problems in the experiment and data collection or is it in fact indicative of an unexpected underlying structure in the data. This determination cannot be made on the basis of statistics alone. The role of the graphical and statistical analysis is to detect problems or unexpected results in the data. Resolving the issues requires the knowledge of the scientist or engineer. Individual Although it is generally unnecessary the plots can be generated Plots individually to give more detail. Since the lag plot indicates significant non-randomness we omit the distributional plots. Run Sequence Plot http div898 handbook eda section4 3 of 4 5 1 2006 9 58 56 AM . Graphical Output and Interpretation Lag Plot NIST SEMATECH HOME TOOLS RAIDS SEARCH BACK NEXT http div898 handbook eda section4 4 of 4 5 1 2006 9 58 56 AM . Quantitative Output and Interpretation TUK PPCC 00 CAUCHY PPCC 00 Location The autocorrelation coefficient of is evidence of significant non-randomness. One way to quantify a change in location over time is to fit a straight line to the data set using the index variable X 1 2 . N with N denoting the number of observations. If there is no significant drift in the location the slope parameter estimate should be zero. For this data set Dataplot generates the following output LEAST SQUARES MULTILINEAR .
