【正文】 ? 結(jié)合目標和需求確定分組的原則 均值控制圖反映的是分組間的過程偏差，范圍控制圖反映的是組內(nèi)的過程偏差。 2023/3/11 40 李健 XR圖計算 ）（ kjXnX niij ??? ??111Xj是每一個采樣數(shù)據(jù) ， k表示采樣的數(shù)據(jù)組數(shù)目 ， n表示每一個采樣組中有 n個數(shù)據(jù) 。 2023/3/11 22 李健 選擇度量的衡量指標（參考） ? It is considered meaningful by the customer,manager,and performer. ? It demonstrated quantifiable correlation between process perturbations and business performance. ? It is objective and unambiguously defined. ? It displays trends. ? It is a natural byproduct of the process. ? It is supported by automation. ? Metrics must be simple,objective,easy to collect,easy to interpret,and hard to misinterpret. ? Metrics collection must be automated and nonintrusive,that is, not interfere with the activities of developers. ? Metrics must provide consistent assessments throughout the life cycle, especially in early phases, when efforts to improve quality have a high payoff. ? Metrics,both values and trends, must be used actively by management and engineering personnel for municating progress and quality in a consistent format. ? Metrics’ fidelity improves across the life cycle. 2023/3/11 23 李健 選擇度量的衡量指標（參考） ? The measures should relate closely to the issue under study. These are usually issues of quality,resource consumption, or elapsed time. ? They should have high information content.. ? They should pass a reality test. ? They should permit easy and economical collection of data. ? They should permit consistently collected , welldefined data. ? They should show measurable variation. ? They should have diagnostic value and be able to help you identify not only that something unusual has happened but also what might be causing it. 2023/3/11 24 李健 選擇度量的標準 ?可交流性 采用規(guī)范的方法對度量屬性進行定義和描述，使其他人可以一致地了解度量的內(nèi)容，度量的數(shù)據(jù)值里包括了哪些信息或不包括哪些信息，以及度量數(shù)據(jù)的收集過程。 ? 顯式度量和隱式度量 – 顯示度量是可直接得到數(shù)據(jù)的度量，例如編程時間是顯式度量。 [ISO/IEC 145981] ? Measurement， 測量，是按照一定的尺度用度量（名詞）給軟件實體屬性賦值的過程 [ISO/IEC 145981]。 ? Process Capability， 軟件過程能力度描述通過遵循軟件過程能夠?qū)崿F(xiàn)預期結(jié)果的程度。 ? 度量方法 ， 對產(chǎn)品的度量方法是階段性方法，度量對象是軟件生產(chǎn)后期得到的成形的軟件產(chǎn)品。 商業(yè)目標 1 商業(yè)目標 2 商業(yè)目標 n ? 關鍵過程目標 1 關鍵過程目標 2 ? 關鍵過程目標 m 度量目標 1 度量目標 2 ? 度量目標 k 2023/3/11 26 李健 過程實體描述模型 過程組成 過程消耗 過程保留 過程輸入 過程輸出 2023/3/11 27 李健 度量的對象內(nèi)容（參考） 1. Work and p