This question's explanation and your answers so far.
あるコールセンタでは, 顧客からの電話による問合せに対応するオペレータを支援するシステムとして, 顧客とオペレータの会話の音声を認識し, 顧客の問合せに対する回答の候補をオペレータの PC の画面に表示する AI を導入した。1日の対応件数は1,000件であり, 問合せ内容によって二つのグループ A, B に分けた。AI 導入前後の各グループの対応件数, 対応時間が表のとおりであるとき, AI 導入後に, 1日分の1,000件に対応する時間は何%短縮できたか。 AI 導入前後のグループ別の対応件数と対応時間
| グループ A 対応件数 | グループ A 対応時間 | グループ B 対応件数 | グループ B 対応時間 | |
|---|---|---|---|---|
| AI 導入前 | 500件 | 全体の80% | 500件 | 全体の20% |
| AI 導入後 | 500件 | AI 導入前と比べて30%短縮 | 500件 | AI 導入前と同じ時間 |
15% comes from mistakenly taking Group A's weight as the “case-count ratio” instead of the “time ratio”. Group A's case count is 500/1,000=50%, giving 0.50×0.30=0.15, but what must be reduced is time, and Group A accounts for 80% of the total time. This confuses the case-count weight with the time weight.
16% results from a baseless calculation such as multiplying the table's 80% by 20% (0.80×0.20=0.16), which does not use the 30% reduction rate at all. Correctly, one multiplies Group A's time ratio of 80% by the 30% reduction rate.
20% comes from mistakenly taking Group B's time ratio of 20% from the table as the answer. Group B's handling time is “the same as before AI” and does not change, so it contributes nothing to the reduction. The reduction arises from the 30% cut on the Group A side.
正解 Let the total daily handling time before AI introduction be 100%. From the table, this breaks down into Group A at 80% of the total and Group B at 20% of the total. After AI introduction, Group A is “reduced by 30% compared with before AI”, so it drops to 80%×(1-0.30)=56%; Group B has “the same time as before AI”, so it stays at 20% unchanged. The total time after introduction is 56%+20%=76%. Therefore the time that can be reduced is 100%-76%=24%. The overall reduction rate can also be computed as “the time share of the part to be reduced (Group A's 80%)” times “its reduction rate (30%)”, i.e. 0.80×0.30=0.24=24%, so the answer is “エ 24”.