問40
頻出度★★★
同一難易度の複数のプログラムから成るソフトウェアのテスト工程での品質管理において, 各プログラムの単位ステップ数当たりのバグ数をグラフ化し, 上限・下限の限界線を超えるものを異常なプログラムとして検出したい。作成する図として, 最も適切なものはどれか。
令和3年度 ITパスポート試験 問40
ストラテジ系企業活動 › 業務分析・データ利活用
This question's explanation and your answers so far.
解説
問 40
- ア
正解 The correct answer is “ア: Control chart”. In addition to the center line (the average) of the data, a control chart draws an upper control limit line (UCL) and a lower control limit line (LCL), and judges whether the process is stable by whether the values plotted in time order stay inside these limit lines. The question asks to plot “the number of bugs per unit number of steps for each program” and to detect as abnormal programs those that exceed the upper and lower limit lines, which is exactly outlier detection using control limit lines, so a control chart is the most appropriate.
Incorrectイ
A cause-and-effect diagram systematically organizes the factors that affect a result (the characteristic) into a fishbone-like shape, and is used to identify causes. It is not intended for drawing upper and lower limit lines to detect abnormal values.
Incorrectウ
A Pareto chart arranges items as a bar chart in descending order of frequency of occurrence, overlays the cumulative ratio as a line, and identifies the items that should be managed as priorities. It has no control limit lines and cannot be used to detect abnormalities by exceeding such lines.
Incorrectエ
A radar chart places multiple evaluation items on radial axes and represents them as a polygon to compare their balance or tendencies. It has no mechanism for time-series plotting or for detecting abnormalities via upper and lower limit lines.
ここがポイント
- Control chart = a chart that draws a center line plus an upper control limit line (UCL) and a lower control limit line (LCL), and detects points that go beyond the limit lines as abnormal (an unstable process).
- Distinguishing the uses of the seven QC tools: control chart = process stability and abnormality detection; cause-and-effect diagram = organizing factors; Pareto chart = narrowing down priority items; radar chart = comparing the balance of multiple items.
用語