Tham khảo tài liệu 'engineering statistics handbook episode 4 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Bias with sparse data ENGINEERING STATISTICS HANDBOOK home TOOLS AIDS ISEAtCH back next 2. Measurement Process Characterization . Uncertainty analysis . Type A evaluations . Type A evaluations of bias . Bias with sparse data Strategy for The purpose of this discussion is to outline methods for dealing with dealing with biases that may be real but which cannot be estimated reliably because limited data of the sparsity of the data. For example a test between two of many possible configurations of the measurement process cannot produce a reliable enough estimate of bias to permit a correction but it can reveal problems with the measurement process. The strategy for a significant bias is to apply a zero correction. The type A uncertainty component is the standard deviation of the correction and the calculation depends on whether the bias is A inconsistent A consistent Example of differences among wiring settings Data on wiring configurations An example is given of a study of wiring settings for a single gauge. The gauge a 4-point probe for measuring resistivity of silicon wafers can be wired in several ways. Because it was not possible to test all wiring configurations during the gauge study measurements were made in only two configurations as a way of identifying possible problems. Measurements were made on six wafers over six days except for 5 measurements on wafer 39 with probe 2062 wired in two configurations. This sequence of measurements was repeated after about a month resulting in two runs. A database of differences between measurements in the two configurations on the same day are analyzed for significance. http div898 handbook mpc section5 1 of 5 5 1 2006 10 12 52 AM . Bias with sparse data Run so ftware macro f for making plotting differences between the 2 wiring configurations A plot of the differences between the 2 configurations shows that the differences for run 1 are for the most .
