慶英会 塾長｜慶應義塾大学卒・英検1級
中高一貫校の学校英語・NEW TREASURE・英検対策を専門とするオンライン個別指導塾です。塾長紹介
英検準2級プラスの長文では、調査結果に「関係があった」と書かれているだけなのに「原因が証明された」と言い換えると、内容一致で失点します。correlation（関連・相関）とcausation（因果関係）を区別し、suggest・may・might・prove・becauseの断定度、調査対象の広さ、同時に変わった条件を読み取ることが重要です。慶英会が作成した独自40問（本文根拠の4択12問・過剰な断定の訂正12問・独自長文4題16問）で、事実と推測を正確に区別します。
結論｜相関は因果関係の証明とは限らない
- correlation / association：二つの事柄に関連があるという観察結果。必ずしも一方が他方の原因とは言えない。
- cause / causation：ある要因が結果を引き起こすという関係。原因と主張するには、他の要因や比較方法の検討が必要。
- suggest / may / might：可能性や示唆を表す。may improveを「必ず改善する」と言い換えない。
- prove / demonstrate：証明・実証に関わる強い表現。本文がsuggestと述べているならproveへ勝手に強めない。
- sample / respondents：回答者・試験対象の範囲。少数の参加者の結果を全生徒・全住民に当てはめない。
例えばアプリ利用者の成績が高かったとしても、もともとよく学習する生徒ほどアプリを使っていた可能性があります。また「照明」と「室温」を同時に変えて結果が改善したとき、照明だけの効果とは断定できません。この教材は科学的な因果推論の入門を、英語の長文内容一致に役立つ読み方へ落とし込んだものです。
公式出題形式との関係
日本英語検定協会の準2級プラスReadingは短文空所補充17問、長文空所補充6問、長文内容一致8問で、教育・科学・自然環境・技術など身近な社会的話題も対象です（公式試験内容）。以下の問題・数値・調査例はすべて慶英会が制作した架空の英文で、英検協会の公式過去問ではありません。
Part 1｜一文の証拠から判断する4択12問
英文と選択肢を比較して、最も根拠のある結論を1つ選びましょう。可能性（may, might）、一部（some）、報告（reported）を「全員」「必ず」「証明」と強めてはいけません。
問1
A survey found that students who read daily often reported high test scores. No experiment was performed. What is justified?
A. Daily reading definitely caused the scores. ／ B. The survey found an association, but not proof of cause. ／ C. All students who read scored highly. ／ D. The survey showed that reading had no value.
問1｜正解・誤答の理由
正解：B. The survey found an association, but not proof of cause.
reported an association only; no experiment controlling other factors。
和訳・要点：毎日読書する生徒は高得点を報告する傾向があったが、因果関係の証明ではない。
問2
The temperature and ice cream sales both rose in July. Which conclusion is safest?
A. Ice cream sales caused the weather. ／ B. There was no change in either figure. ／ C. Both increased during July, but a cause has not been established. ／ D. Every customer visited because it was hot.
問2｜正解・誤答の理由
正解：C. Both increased during July, but a cause has not been established.
二つの変化を観察しただけでは原因を確定できない。
和訳・要点：7月には気温とアイスの販売数がともに上がったが、原因は証明されていない。
問3
An article says a new course ‘may help’ students. Which paraphrase preserves its meaning?
A. The course might help students. ／ B. The course will help every student. ／ C. The course has been proven to work. ／ D. The course cannot help students.
問3｜正解・誤答の理由
正解：A. The course might help students.
mayは可能性であって保証ではない。
和訳・要点：その講座は生徒を助ける可能性がある。
問4
Researchers tested a tool in one small class. Which conclusion avoids overgeneralization?
A. It works in all schools. ／ B. It has been proved effective for everyone. ／ C. It is useless outside the class. ／ D. It was tested in one class; wider results remain uncertain.
問4｜正解・誤答の理由
正解：D. It was tested in one class; wider results remain uncertain.
試験対象は一クラスだけ。
和訳・要点：一つのクラスで試験したが、広い範囲への適用は不明だ。
問5
A report says ‘Participants said they felt more confident.’ Which is supported?
A. Their scores certainly doubled. ／ B. Participants reported a feeling of greater confidence. ／ C. All participants achieved the same grade. ／ D. The teacher measured a permanent ability increase.
問5｜正解・誤答の理由
正解：B. Participants reported a feeling of greater confidence.
reported feelingsと客観的な成績の変化は別。
和訳・要点：参加者は自信が増したと自己申告した。
問6
A school compared results before and after a new schedule. Other changes also occurred. What is a limitation?
A. No one took a test. ／ B. The schedule had no effect. ／ C. Other changes might have influenced the result. ／ D. All improvement was caused by the schedule.
問6｜正解・誤答の理由
正解：C. Other changes might have influenced the result.
同時に別の条件も変わった。
和訳・要点：他の変化が結果に影響した可能性がある。
問7
A local survey asked 40 volunteers but the town has 20,000 residents. What cannot be assumed?
A. That the 40 answered the survey. ／ B. That the town has residents. ／ C. That volunteers can have opinions. ／ D. That the answers represent all 20,000 residents.
問7｜正解・誤答の理由
正解：D. That the answers represent all 20,000 residents.
回答者と住民全体は違う。
和訳・要点：40人の回答を2万人全員の意見とみなせない。
問8
A trial found fewer errors after additional training. Which statement is properly cautious?
A. Errors were lower after training, but other explanations need checking. ／ B. Training is the sole proven reason. ／ C. Errors became impossible. ／ D. No comparison was made.
問8｜正解・誤答の理由
正解：A. Errors were lower after training, but other explanations need checking.
前後比較は事実だが、単独の原因とは限らない。
和訳・要点：研修後に誤りが減ったが、他の説明も検討する必要がある。
問9
The notice says ‘The results suggest a possible benefit.’ Which is accurate?
A. The benefit is guaranteed. ／ B. The results indicate a possible benefit. ／ C. The result is definitely negative. ／ D. Every customer benefited.
問9｜正解・誤答の理由
正解：B. The results indicate a possible benefit.
suggest / possible は不確実性を残す。
和訳・要点：結果は利益がある可能性を示唆している。
問10
An experiment changed both lighting and room temperature. Which claim is not established?
A. Both conditions changed. ／ B. Participants completed a task. ／ C. Lighting alone caused any improvement. ／ D. The team can review its data.
問10｜正解・誤答の理由
正解：C. Lighting alone caused any improvement.
照明と室温を同時変更したので照明だけの効果は特定不可。
和訳・要点：改善が照明だけによるものとは確定できない。
問11
A town reports that buses carried 30 more people in August. Which is a fact directly supported?
A. Buses carried 30 more people in August. ／ B. The new route was certainly the cause. ／ C. Every resident now takes the bus. ／ D. Passenger numbers doubled.
問11｜正解・誤答の理由
正解：A. Buses carried 30 more people in August.
30人増という結果だけが提示された。
和訳・要点：8月のバス利用者は30人増加した。
問12
A study could not determine which factor caused a change. What is the safest summary?
A. The cause was proved. ／ B. All possible factors were excluded. ／ C. No change happened. ／ D. The observed change had no established single cause.
問12｜正解・誤答の理由
正解：D. The observed change had no established single cause.
原因が特定できなかったという限定を守る。
和訳・要点：観測された変化について単一の原因は確立されていない。
Part 2｜本文より強すぎる断定を訂正する12問
次の英文には「関係があった→原因が確定」「一部→全員」「可能性→必然」などの飛躍があります。元の事実を損なわず慎重で正確な英文に書き換え、模範解答と比較してください。
問13
Students who used the app scored higher; therefore the app definitely raised their scores.
問13｜訂正後の英文と理由
Students who used the app scored higher, but the report did not prove that the app caused the difference.
相関だけで原因を断定した箇所を修正する。
和訳：アプリ利用者の得点は高かったが、アプリが差を生んだとは証明されていない。
問14
The survey of 20 volunteers proves what every student in the school thinks.
問14｜訂正後の英文と理由
The survey reports the opinions of 20 volunteers, not necessarily every student in the school.
回答者の範囲をそのまま示す。
和訳：調査は20人のボランティアの意見であり、全校の意見とは限らない。
問15
The new schedule may reduce waiting time, so it will certainly do so.
問15｜訂正後の英文と理由
The new schedule may reduce waiting time, but that outcome is not certain.
mayをwill certainlyに強めない。
和訳：新日程で待ち時間は減るかもしれないが確実ではない。
問16
After the library changed its opening hours, visits rose. The schedule was the only cause.
問16｜訂正後の英文と理由
Visits rose after the opening hours changed, but other factors may also have contributed.
他の原因を排除していない。
和訳：開館時間変更後に来館者は増えたが、ほかの要因も関係した可能性がある。
問17
Some participants reported satisfaction, so all participants were satisfied.
問17｜訂正後の英文と理由
Some participants reported satisfaction; the report does not say that everyone was satisfied.
someをallに変えない。
和訳：満足したと答えた参加者は一部であり、全員とは書かれていない。
問18
The experiment showed promising results, so the method must be effective for every age group.
問18｜訂正後の英文と理由
The experiment showed promising results, but its effectiveness for every age group was not established.
試験した範囲を超えない。
和訳：期待できる結果は得られたが、全ての年齢層への有効性は確立されていない。
問19
A museum had more visitors during a festival, so festivals always increase visits.
問19｜訂正後の英文と理由
The museum had more visitors during this festival; it is unclear whether every festival has the same effect.
特定事例から常にと一般化しない。
和訳：この祭りの期間は来館者が増えたが、毎回そうなるかは不明。
問20
The report suggests that reading may help; therefore reading has no possible benefit.
問20｜訂正後の英文と理由
The report suggests that reading may help, although the effect is not certain.
可能性の示唆を無益という結論に反転しない。
和訳：読書が役立つ可能性は示唆されているが、効果は確実ではない。
問21
The number of survey responses rose from 40 to 60, proving public support increased.
問21｜訂正後の英文と理由
Survey responses rose from 40 to 60, but that alone does not prove public support increased.
回答数と支持割合は別。
和訳：回答数は40から60に増えたが、それだけで支持が増えたとは証明できない。
問22
The students’ scores rose when two teaching methods changed; only method A caused it.
問22｜訂正後の英文と理由
Scores rose after both teaching methods changed, so the separate effect of method A is unknown.
同時変更でAだけの寄与は不明。
和訳：2種類の方法が変わって得点が上がったが、A単独の効果は不明だ。
問23
Some parents preferred printed information, so digital information should be removed for everyone.
問23｜訂正後の英文と理由
Some parents preferred printed information, but this does not show that digital information is unnecessary for everyone.
好みの一部回答から全体方針を断定しない。
和訳：紙を好む保護者もいたが、すべての人にデジタル情報が不要とは言えない。
問24
A larger sample was used, so every possible source of error has disappeared.
問24｜訂正後の英文と理由
A larger sample was used, but some sources of error may still remain.
標本拡大でもバイアス等は残り得る。
和訳：標本を増やしても誤差の原因がすべて消えるわけではない。
Part 3｜研究・学校・地域の独自4長文16問
長文の根拠を読むときは「実際に観察したこと」「まだ不明なこと」「予定される追加調査」を3つに分けます。正答は本文の主語・数字・可能性の表現と一致する選択肢です。
長文1｜読書アプリとテスト結果
Reading passage（慶英会オリジナル）
A junior high school surveyed 120 students about their study habits. Seventy students said they used an English reading app at least three times a week. Their average test score was higher than that of the other fifty students. Some teachers wanted to conclude that the app had caused the difference. However, the researcher said the survey could only show a relationship between app use and test scores. The students had chosen whether to use the app, and the survey did not measure how much time they spent studying outside the app. The school decided to collect more information before making the app a required part of lessons. It also planned a small voluntary trial comparing learning activities under more similar conditions. The report emphasized that a useful observation is not the same as a proven cause.
問25. How many students said they used the app at least three times a week?
A. 50 ／ B. 70 ／ C. 100 ／ D. 120
問25｜正解と本文根拠
正解：B. 70
Seventy students said they used the app。
問26. What did the survey observe?
A. App users had higher average scores. ／ B. The app guaranteed higher scores. ／ C. Every student used the app. ／ D. No student studied outside the app.
問26｜正解と本文根拠
正解：A. App users had higher average scores.
their average test score was higher。
問27. Why did the researcher avoid claiming a proven cause?
A. The survey had no students. ／ B. The test scores were not recorded. ／ C. Students chose whether to use the app and other study time was not measured. ／ D. The app had been required for years.
問27｜正解と本文根拠
正解：C. Students chose whether to use the app and other study time was not measured.
self-selectionとアプリ外学習時間未調査が制約。
問28. What did the school decide?
A. Require the app immediately for everyone. ／ B. Cancel all reading lessons. ／ C. Declare the app ineffective. ／ D. Collect more information before making the app required.
問28｜正解と本文根拠
正解：D. Collect more information before making the app required.
collect more information before making required。
長文1｜全文和訳
中学校は120人に学習習慣を調査した。70人が英語読書アプリを週3回以上使用し、その平均点は残る50人より高かった。先生の中にはアプリが差を生んだと結論付けたい人もいた。しかし研究担当者は、調査で示せるのはアプリ使用と得点の関連だけだと述べた。生徒は自分でアプリを使うか選んでおり、アプリ外の勉強時間は調べていなかった。学校は授業での必須化を決める前に情報を増やし、似た条件で任意参加の小規模な比較も計画した。役立つ観察結果と証明された原因は別だと報告書は強調した。
長文2｜公園の来訪者とアイスの売上
Reading passage（慶英会オリジナル）
A public park counted visitors and ice cream sales during the summer. On warmer weekends, both numbers usually increased. A local shop owner claimed that selling more ice cream was bringing more visitors to the park. Park staff said this conclusion was not established by the data. Warm weather might have encouraged both park visits and ice cream purchases. In addition, summer events attracted families on some weekends, but there was no event every week. The team therefore decided to compare similar weekends and record event schedules and weather conditions. The report stated that the two numbers changed together during the period studied. It did not claim that one change directly caused the other. The park also noted that unusually hot days could reduce visits, so simple predictions based on temperature alone might be unreliable.
問29. What generally happened on warmer weekends?
A. Both visits and ice cream sales increased. ／ B. Both numbers were always zero. ／ C. Only shop hours changed. ／ D. Park visits doubled every time.
問29｜正解と本文根拠
正解：A. Both visits and ice cream sales increased.
both numbers usually increased。
問30. What alternative explanation did park staff offer?
A. All visitors were shop employees. ／ B. The park had no events. ／ C. Warm weather might encourage both activities. ／ D. Ice cream sales were never recorded.
問30｜正解と本文根拠
正解：C. Warm weather might encourage both activities.
warm weather might have encouraged both。
問31. What information will the team record when comparing weekends?
A. Only the number of employees. ／ B. Weather and event schedules. ／ C. Only the ice cream flavors. ／ D. Visitors’ addresses.
問31｜正解と本文根拠
正解：B. Weather and event schedules.
record event schedules and weather conditions。
問32. What did the report NOT establish?
A. That the two numbers changed together. ／ B. That some summer events attracted families. ／ C. That not every week had an event. ／ D. That ice cream sales directly caused more park visits.
問32｜正解と本文根拠
正解：D. That ice cream sales directly caused more park visits.
did not claim one change directly caused the other。
長文2｜全文和訳
公園は夏の来訪者数とアイスの売上を記録した。暖かい週末には両方が増える傾向があった。店主はアイスの売上増が公園の来訪者を増やしたと主張したが、職員はその因果関係はデータから確立されていないと述べた。暖かい天気が来園とアイス購入の両方を促した可能性がある。また夏の行事が家族を引き付けた週末もあったが毎週ではない。そこで天候と行事日程も記録し、似た週末を比較することにした。報告書が述べたのは研究期間中に二つの数が一緒に変化したという点だけで、一方が他方を直接引き起こしたとはしていない。極端に暑い日は来園者が減ることもあるため、気温だけの単純な予測は危ういとも指摘した。
長文3｜理科室の学習環境
Reading passage（慶英会オリジナル）
A school tested whether students could read instructions more easily in a different classroom. In the original room, some students complained that the lights were dim and the temperature was uncomfortable. The school moved one class to a brighter room with a more comfortable temperature. After the move, fewer students said they had trouble reading the instructions. The teacher welcomed the result, but warned that the school had changed two conditions at the same time. It was therefore impossible to identify the separate effect of lighting from this comparison alone. The students suggested a future study that would measure lighting while keeping other important conditions as similar as possible. The report described the change in students’ responses and stated a limitation rather than claiming that better lighting alone had solved the problem.
問33. Which two conditions changed when the class moved?
A. Only the teacher and subject. ／ B. The number of desks and textbooks. ／ C. The building’s opening hours. ／ D. Lighting and temperature.
問33｜正解と本文根拠
正解：D. Lighting and temperature.
brighter room with a more comfortable temperature。
問34. What happened after the move?
A. More students reported trouble. ／ B. Fewer students reported difficulty reading instructions. ／ C. All students received perfect grades. ／ D. The school stopped experiments.
問34｜正解と本文根拠
正解：B. Fewer students reported difficulty reading instructions.
fewer students said they had trouble reading。
問35. Why could the teacher not isolate the effect of lighting?
A. Two conditions had changed together. ／ B. No student changed classrooms. ／ C. Lighting was measured in every room. ／ D. All students were absent.
問35｜正解と本文根拠
正解：A. Two conditions had changed together.
changed two conditions at the same time。
問36. What did students propose for a future study?
A. Never measuring lighting again. ／ B. Changing every variable together. ／ C. Keeping other conditions similar while studying lighting. ／ D. Testing only in the original room forever.
問36｜正解と本文根拠
正解：C. Keeping other conditions similar while studying lighting.
keeping other conditions as similar as possible。
長文3｜全文和訳
学校は別の教室で生徒が指示を読みやすくなるか調べた。以前の部屋では照明が暗く室温も不快だと訴える生徒がいた。学校は一クラスを明るく温度も快適な部屋へ移した。移動後には指示を読むのが難しいと答える生徒が減った。先生は結果を歓迎したが、二つの条件を同時に変えたと注意した。よってこの比較だけで照明単独の効果を特定できない。生徒たちは他の重要条件をできるだけそろえ、照明の違いを測る研究を提案した。報告書では回答の変化と研究の限界を説明し、照明だけが問題を解決したと主張しなかった。
長文4｜地域バスの利用者数と施策
Reading passage（慶英会オリジナル）
A town introduced a new evening bus route and started an advertising campaign during the same month. Passenger numbers rose from 200 per week to 260 per week. Some residents celebrated the increase and said that the route alone had caused it. The transport office responded that both the route and the advertising had changed, while seasonal travel patterns could also have influenced demand. The observed increase was 60 passengers per week, or 30 percent of the earlier total. The office did not know how many additional passengers were due to each factor. It planned to compare later months and ask passengers why they used the service. Although the town was pleased with the result, it did not promise that passenger numbers would continue to rise every month.
問37. How many additional weekly passengers were recorded?
A. 30 ／ B. 60 ／ C. 200 ／ D. 260
問37｜正解と本文根拠
正解：B. 60
260−200=60。
問38. What else changed when the new route began?
A. The school year ended. ／ B. All bus fares were removed. ／ C. An advertising campaign started. ／ D. The train station closed.
問38｜正解と本文根拠
正解：C. An advertising campaign started.
started an advertising campaign during the same month。
問39. Why could the office not credit the new route alone?
A. Advertising and seasonal patterns could also affect demand. ／ B. The passenger figures were identical. ／ C. No one used the new route. ／ D. The town had canceled the service.
問39｜正解と本文根拠
正解：A. Advertising and seasonal patterns could also affect demand.
both changes and seasonal travel patterns possible。
問40. What did the office NOT promise?
A. To compare later months. ／ B. To ask passengers why they ride. ／ C. To study different causes. ／ D. That passenger numbers would grow every month.
問40｜正解と本文根拠
正解：D. That passenger numbers would grow every month.
did not promise passenger numbers would continue to rise every month。
長文4｜全文和訳
町は新しい夕方のバス路線を導入すると同時に広告活動を始めた。週の乗客数は200人から260人へ増えた。一部の住民は路線だけの効果だと考えたが、交通担当部署は路線と広告の両方が変化したうえ、季節的な移動需要も影響した可能性があると説明した。増加は週60人、元の200人に対し30%だった。どの要因が何人分の増加につながったかは不明だった。部署は今後の月を比較し利用理由を乗客に尋ねる予定だ。結果には満足していたが、毎月利用者が増え続けるとは約束しなかった。
解き直し｜「主張の強さ」を5段階で確認
- 本文のclaim、report、suggest、may、proveなどの動詞・助動詞を下線で示し、断定の程度を確認する。
- 原因を述べる選択肢について、その要因以外の条件が変わっていなかったか調べる。
- 調査参加者が自ら選んだグループ（self-selected group）なら、ほかの学習習慣が異なる可能性も考える。
- 回答者（respondents）と対象者全体（participants）を混同せず、母数の違いを説明する。
- 翌日と1週間後に4長文を再解答し、正解だけでなく不適切な因果断定を指摘する。
FAQ
correlationがあればcausationが証明されますか？
いいえ。関連が観察されても一方が他方の原因だとは限りません。第三の要因や元からある差の可能性などを検討する必要があります。
suggestとproveの違いは？
suggestは可能性や傾向を示唆する、proveは証明するという強い表現です。本文がsuggestsとあるなら、正解選択肢でも「示唆した」という慎重さを保つことが重要です。
英検のReadingで科学知識は必要ですか？
詳しい科学知識より、本文の事実・条件・結果を正確に読み取ることが基本です。本文が「可能性」と述べているのに自分の常識で「確定」と判断しないようにしましょう。
関連する慶英会無料教材
- majority・minority・most・not all｜調査範囲の独自40問
- twice・half・double｜数値比較の独自40問
- evidence・proof・clue・sign｜証拠・証明の独自40問
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参考にした公式情報：日本英語検定協会「準2級プラスの試験内容」。英文、研究設定、問題、解答、和訳はすべて慶英会独自の練習用素材です。
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