Percent、Percentage 同 Percentage Points:細細個字,大大個錯
有個學生曾經喺一段圖表描述裏面寫:「Unemployment increased by 5 percent, from 30 percent to 35 percent.」聽落幾合理,直到你計過條數。由 30% 升到 35% 係增加咗 5 percentage points,而唔係 5 percent。(30 嘅 5 percent 只係 1.5。)三個細細個字,三個好唔同嘅意思。
點解咁緊要
圖表、調查、新聞報道同商業電郵裏面充滿百分比。當你喺學術題目寫數據,又或者喺會議裏面描述銷售數字嘅時候,用錯個字可以將意思偏差一大截。在意數字嘅讀者會察覺到,而一個粗心嘅措辭可以令一個本來自信嘅講者顯得唔肯定。好消息係規則好短,而一旦你睇通個規律,你就唔會再搞亂佢哋。
規律
Percent(或者符號 %)用喺一個具體數字。你講「twenty-five percent」或者寫「25%」。佢好似一個附喺數字上面嘅單位咁運作。
Percentage 係一個一般名詞。佢用喺冇具體數字嘅情況,通常配 a、the、small、large 或者 what 呢類字。你講「a small percentage of students」或者「what percentage of the budget」。
Percentage point(或者 percentage points)量度兩個百分比之間嘅算術差距。如果一個分數由 70% 變成 75%,佢就升咗 5 percentage points,而唔係 5 percent。
三個快速例子:
- 大約 40 percent 嘅顧客有回應。
- 只有 a small percentage 嘅顧客有回應。
- 回應率由 30% 升到 40%,即係增加咗 10 percentage points。
錯誤 / 自然 / 點解
| 錯誤 | 自然 | 點解 |
|---|---|---|
| Sales increased by 10 percent, from 20% to 30%. | Sales increased by 10 percentage points, from 20% to 30%. | 兩個百分比之間嘅差距用 percentage points 量度,唔係 percent。 |
| What percent of the class passed? | What percentage of the class passed? | 冇具體數字嘅時候,用 percentage。 |
| A small percent of users complained. | A small percentage of users complained. | 冇數字嘅時候,percentage 係名詞形式。 |
| The price increased to 15%. | The price increased by 15%. | By 顯示變化嘅幅度;to 就會解作升到 15% 呢個數值。 |
| Twenty-five percents of the budget is gone. | Twenty-five percent of the budget is gone. | Percent 附喺數字上面時冇複數 -s。 |
| The approval rating dropped by three percent. | The approval rating dropped by three percentage points. | 比較兩個百分比數值時,用 percentage points 嚟避免歧義。 |
| Almost 80 percentage of the seats were filled. | Almost 80 percent of the seats were filled. | 具體數字配 percent,唔係 percentage。 |
常見情境
描述折線圖。「The unemployment rate rose from 4% in January to 6% in June, an increase of two percentage points.」留意 percentage points 點樣清楚噉標示嗰個差距。
報告調查結果。「About 65 percent of respondents said they were satisfied. Only a small percentage gave a negative answer.」第一句有數字,所以用 percent。第二句係一般陳述,所以用 percentage。
講考試分數。「My reading score went up 8 percentage points, from 22 to 30 (out of 30).」如果你講 8 percent,聽者可能會諗 8 percent of what。
商業會議。「Our market share grew from 12% to 18% last year — six percentage points of growth, which is roughly a 50 percent increase relative to where we started.」呢句兩者都用咗:絕對差距用 percentage points,相對變化用 percent。
讀新聞標題。「Inflation eased by 0.3 percentage points.」財經記者對呢個分別好嚴謹,因為一個粗心嘅 percent 可以誤導讀者。
選舉報道。「The candidate's support climbed by four percentage points after the debate.」講 four percent 就會暗示 4% 嘅相對升幅,細好多。
常見錯誤
- 比較兩個百分比嘅時候用 percent —— 應該用 percentage points。
- 講 percents 加 -s。Percent 配任何數字都維持不變。
- 將 by 同 to 搞亂:increased by 10%(變化幅度係 10%)對 increased to 10%(新總數係 10%)。
- 喺 percentage 後面唔記得加 of:係「a percentage of the population」,唔係「a percentage the population」。
- 喺具體數字用 percentage —— 要講「30 percent」,唔係「30 percentage」。
- 喺圖表上將「rose 5 percent」同「rose 5 percentage points」當成一樣。佢哋幾乎永遠都唔係一樣。
- 將「% point」當成一個數學符號咁寫。要寫晒出嚟:percentage points。
迷你練習
填空或者改正句子。
- About 40 ______ of the survey responses came from Europe.
- A small ______ of students chose the elective course.
- The interest rate increased from 3% to 4.5%, a rise of 1.5 ______ ______.
- What ______ of your salary goes to rent?
- Fix: "The approval rating dropped by five percent, from 60% to 55%."
總結
具體數字用 percent,冇數字嘅一般陳述用 percentage,而量度兩個百分比之間嘅差距就用 percentage points。竅門係問自己:我係咪附緊一個數字?我係咪一般噉講?定係我係喺比較兩個比率? 將問題配返個字,你嘅數據句子就會聽落利落又自信。
想喺真實考試句子裏面練習數字、量詞同單位?喺 ExamRift 開始練習。