Question

Read the following newspaper report: In a new study by Harvard School of Public Health (HSPH), researchers explored how caffeine can serve as a “mild anti-depressant”. They concluded that “drinking several cups of coffee daily appears to reduce the risk of suicide”. Data pulled in from three large studies in the US showed that the suicide risk of those who drank two to four cups of caffeinated coffee a day was about half of those who drank decaffeinated coffee or very little or no coffee. In the studies, a respondent’s caffeine consumption was assessed every four years through a questionnaire. The respondents were all adults, and the study was published online. The authors, however, cautioned the public from increasing coffee intake as it could result in “unpleasant side effects”. “Overall, our results suggest that there is little further benefit for consumption above two to three cups/day or 400 mg of caffeine/day,” wrote the researchers. The authors observed that there was no major difference in suicide risk for adults who drank two to three cups a day from those who drank four cups or more. Which of the following shaped graph would best capture the above paragraph (x-axis represents “coffee intake” and y-axis represents “suicidal tendency”)?

• A. A straight line
• B. Saw tooth curve
• C. S shaped curve
• D. U shaped curve
• E. L shaped curve

Hint:

When interpreting such graph-based questions, focus on where the curve changes slope—sharp drops followed by plateaus are typical indicators of L-shaped graphs.

Answer 1

Answer: (E)

Step 1: Understanding the relationship described.
- People who drink no coffee or very little have a higher suicide risk.
- Suicide risk decreases significantly for those who drink 2–4 cups daily.
- Beyond 2–3 cups, there is no major additional benefit (the curve flattens).
Step 2: Graph shape analysis.
- At low coffee intake (near 0), suicide tendency is high.
- As coffee intake increases to 2–3 cups, suicide tendency drops sharply.
- Beyond 3–4 cups, the curve levels off, showing no further reduction.
Step 3: Matching with given options.
(A) Straight line → implies constant reduction/increase, not true.
(B) Saw tooth curve → implies oscillations, not true.
(C) S shaped curve → implies initial slow change, then steep, then plateau; but here the drop is sharp initially and then flat.
(D) U shaped curve → implies risk increases again at higher intake, which is not observed.
(E) L shaped curve → correctly represents sharp initial drop and then flattening out at lower risk. \[ \boxed{\text{The correct graph is L-shaped (Option (E).}} \]