tailieunhanh - Engineering Statistics Handbook Episode 5 Part 15

Tham khảo tài liệu 'engineering statistics handbook episode 5 part 15', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Model Fitting - Initial Model HOME tools i AIDS search s EMATECH SACK NEXT http div898 handbook pmd section6 2 of 2 5 1 2006 10 22 34 AM . Graphical Residual Analysis - Initial Model Residual plots of interest for this model include 1. residuals versus the predictor variable 2. residuals versus the regression function values 3. residual run order plot 4. residual lag plot 5. histogram of the residuals 6. normal probability plot A plot of the residuals versus load is shown below. Hidden Structure Revealed a 8 0 0 500000 1000000 1500000 2000000 2500000 3000000 Load Scale of Plot Key The structure in the relationship between the residuals and the load clearly indicates that the functional part of the model is misspecified. The ability of the residual plot to clearly show this problem while the plot of the data did not show it is due to the difference in scale between the plots. The curvature in the response is much smaller than the linear trend. Therefore the curvature is hidden when the plot is viewed in the scale of the data. When the linear trend is subtracted however as it is in the residual plot the curvature stands out. The plot of the residuals versus the predicted deflection values shows essentially the same structure as the last plot of the residuals versus load. For more complicated models however this plot can reveal problems that are not clear from plots of the residuals versus the predictor variables. http div898 handbook pmd section6 2 of 4 5 1 2006 10 22 34 AM