UPSC Prelims 1999 · General Studies
Question 146: Data Interpretation
In an office, the distribution of work hours is as shown in the following table: No. of Staff Members | No. of hours worked 5 | 0 – 19 12 | 20 – 24 25 | 25 – 29 40 | 30 – 34 15 | 35 – 39 8 | 40 – 45 Consider the following inferences drawn from the table: I. The average number of hours worked by a staff member is about 30. II. The percentage of those who worked 35 or more hours is less than 25. III. At least 5 staff members worked more than 44 hours. Which of these inferences is/are valid?
AnswerThe answer is (c).
Total staff = 5 + 12 + 25 + 40 + 15 + 8 = 105. I: with class midpoints (9.5, 22, 27, 32, 37, 42.5), total hours = 47.5 + 264 + 675 + 1280 + 555 + 340 = 3161.5, so the average is about 30.1: valid. II: those working 35 or more = 15 + 8 = 23 of 105, about 21.9 per cent, under 25: valid. III: the 40-45 class has 8 people, but the table does not show how many worked beyond 44, so this cannot be concluded.
- I. Average about 3161.5 / 105 = 30.1 hours.
- II. 23 of 105 is about 21.9 per cent, below 25.
- III. The table does not say how many worked more than 44 hours.
Why each option is right or wrong
- (a) Wrong. II is also valid.
- (b) Wrong. I is also valid.
- (c) Right. I and II are valid.
- (d) Wrong. III cannot be concluded from the table.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 1999, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.