問31
頻出度★★★
コールセンタの顧客サービスレベルを改善するために, 顧客から寄せられたコールセンタ対応に関する苦情を分類集計する。 苦情の多い順に, 件数を棒グラフ, 累積百分率を折れ線グラフで表し, 対応の優先度を判断するのに適した図はどれか。
令和4年度 ITパスポート試験 問31
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 31
Incorrectア
A PERT chart uses arrows and nodes to represent the order and duration of tasks, and is a schedule-management diagram for finding a project's earliest/latest schedule and its critical path. It is not used to arrange complaint counts from most to least in order to decide priority.
Incorrectイ
A control chart plots measured values arranged in time order, together with a center line and upper and lower control-limit lines, to monitor whether a process is in a stable state (whether abnormalities exist). It is not a bar chart ordered by frequency plus a cumulative line, and it is not a tool for judging priority.
Incorrectウ
A cause-and-effect diagram (fishbone diagram) organizes the possible factors for a given result (characteristic) into main bones and small bones, systematically drawing out the causes. It is suited to cause analysis, but it does not show a bar chart ordered by frequency or a cumulative percentage, and it is not a diagram for judging the priority of handling from counts.
- エ
正解 “エ Pareto chart” is the correct answer. A Pareto chart overlays on a single figure a bar chart in which items (here, the categories of complaints) are arranged from the most frequent to the least, together with a line chart showing their cumulative percentage. It visualizes the tendency for a few top items to account for most of the whole (the Pareto principle), making it ideal for deciding which complaints to handle first. The wording in the question — showing counts as a bar chart and the cumulative percentage as a line chart to judge the priority of handling — matches the definition of a Pareto chart exactly.
ここがポイント
- Pareto chart = a bar chart ordered from most to least frequent + a line chart of the cumulative percentage. It is used to visualize the share that the top items occupy of the whole, and thereby to judge which items to focus on (priority); it is the basis of ABC analysis.
- Identifying the seven QC tools: be able to distinguish the Pareto chart (key items), the cause-and-effect diagram (cause analysis), and the control chart (monitoring process abnormalities) by their respective purposes and appearances.
用語