問38
頻出度★★★
システム開発プロジェクトの品質目標を検討するために, 複数の類似プロジェクトのプログラムステップ数と不良件数の関係性を示す図として, 適切なものはどれか。
令和5年度 ITパスポート試験 問38
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 38
Incorrectア
A control chart arranges a process's measured values in time order and monitors whether the process is in a stable state using a center line and upper and lower control limits. It is used to manage variation over time, not to show the relationship between two variables, so it is not appropriate.
- イ
正解 The question asks for a diagram that shows the relationship (correlation) between two sets of numeric data: the number of program steps and the number of defects. The diagram that plots the corresponding values of two variables as points on the vertical and horizontal axes, letting you read whether they are correlated and the overall trend, is the scatter plot (イ); by plotting each of several similar projects as a single point, you can visually grasp a relationship such as 'as the number of steps increases, the number of defects also increases'. Therefore the scatter plot is the appropriate choice for examining quality targets.
Incorrectウ
A cause-and-effect diagram (fishbone diagram) organizes the factors that affect a certain result (characteristic) in a fish-bone shape to identify causes. Its purpose is to classify and organize factors, not to show the correlation between two sets of numeric data, so it is not appropriate.
Incorrectエ
A Pareto chart arranges item-by-item data as bars in descending order and overlays the cumulative ratio as a line, and it is used to find the 'vital few' that should be addressed with priority. It is not a diagram that shows the relationship between two variables, so it is not appropriate.
ここがポイント
- Among the seven QC tools, the one that shows the correlation and relationship between two variables (for example, the number of program steps and the number of defects) through the scatter of points is the scatter plot.
- Remember the distinct purpose of each diagram: control chart = time-series monitoring of a process, cause-and-effect diagram = organizing factors, Pareto chart = identifying priority items.
用語