問8
頻出度★★★
不良品や故障, クレームなどの件数を原因別や状況別に分類し, それを大きい順に並べた棒グラフと, それらの累積和を折れ線グラフで表した図はどれか。
平成29年度 秋期 ITパスポート試験 問8
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 8
Incorrectア
A control chart plots measured values along the passage of time and draws a center line together with upper and lower control limits to monitor whether the process is stable (whether there is abnormal variation). It is neither a bar chart arranging counts in descending order nor a cumulative-total line chart, so it is wrong.
Incorrectイ
A tree diagram (systematic diagram) organizes the means for achieving an objective by expanding them from higher to lower levels in a branching (tree-like) form. It does not express the magnitude of counts with a bar chart or a cumulative line, so it is wrong.
- ウ
正解 The correct answer is “ウ Pareto chart.” A Pareto chart classifies the number of defective products, failures, complaints, and so on by cause or by situation, arranges them as a bar chart in descending order of count, and then overlays a line chart of the cumulative ratio obtained by adding up each item’s proportion from largest to smallest. The two features stated in the question — “a bar chart arranged in descending order” and “the cumulative total shown as a line chart” — match exactly the definition of a Pareto chart. As the basis of ABC analysis for priority management, it is used to see at a glance which cause accounts for the majority of the whole.
Incorrectエ
A matrix diagram places two or more elements in rows and columns and organizes the correspondence, or the presence and degree of relation, at their intersections. It is not a combination of a bar chart and a cumulative line, so it is wrong.
ここがポイント
- Pareto chart = a bar chart with counts arranged in descending order + a line chart of the cumulative ratio (cumulative total). It visualizes which cause accounts for the majority of the whole and is used for priority management through ABC analysis.
- Distinguish the control chart (monitoring process stability), one of the QC Seven Tools, from the tree diagram (branching expansion of means) and the matrix diagram (organizing row × column correspondence), which belong to the New QC Seven Tools, by their respective uses and visual differences.
用語