Level 1
Statistics MCQs set 2 for EOBI Officer / Assistant (NTS) Mathematics — 20 solved questions.
Q1. Loan instalments in thousands Rs were 25, 27, 29, 31 and 33. What is the median instalment in thousands Rs?
Answer: 29
Explanation: Sorted: 25, 27, 29, 31, 33; with 5 values the median is the 3rd = 29 thousand rupees.
Q2. Perimeters measured on five rectangular plots were 120 m, 124 m, 128 m, 132 m and 136 m. What is the mean perimeter in metres?
Answer: 128
Explanation: Mean = (120 + 124 + 128 + 132 + 136) ÷ 5 = 640 ÷ 5 = 128 m.
Q3. City bus passengers counted each trip were 37, 39, 41, 43 and 45. What is the range of passenger counts?
Answer: 8
Explanation: Range = maximum − minimum = 45 − 37 = 8 passengers.
Q4. Share prices over six sessions closed at Rs 180 each day except once when they closed at Rs 204. Which summary equals Rs 184 per session if misapplied as a typical closing price for each session?
Answer: Mean closing price
Explanation: Mean = (180×5 + 204)/6 = (900+204)/6 = 1104/6 = Rs 184; the mean closing price equals Rs 184.
Q5. Worker ratios completing tasks were summarised by counts 12 workers fast, 18 steady and 30 slow out of 60 sampled. Which fraction equals the proportion of steady workers in this sample?
Answer: 3/10
Explanation: 18 out of 60 workers are steady, and 18/60 simplifies to 3/10 by dividing numerator and denominator by 6.
Q6. Quiz marks were 55, 60, 65, 70 and 75 each weighted equally toward the course grade. A student mistakenly averages only the lowest and highest marks. By how many marks does this wrong mid‑range exceed the true mean mark?
Answer: 0
Explanation: True mean = (55+60+65+70+75)/5 = 65; mid-range = (55+75)/2 = 65 as well, so the difference is 0.
Q7. Seed germination counts out of 100 pots were 90, 92, 94, 96 and 98 successful sprouts. What is the median germination count?
Answer: 94
Explanation: Sorted: 90, 92, 94, 96, 98; the middle (3rd) value is 94.
Q8. Tax slabs contributed revenues Rs 400000, 410000, 420000, 430000 and 600000 from districts A through E respectively. What is the median revenue contribution in Rs?
Answer: 420000
Explanation: Arranging the five values in order (400000, 410000, 420000, 430000, 600000), the middle (3rd) value is 420000, which is the median.
Q9. Lengths of fence repaired each day were 15 m, 18 m, 18 m, 22 m and 27 m. What is the mode length in metres?
Answer: 18
Explanation: The mode is the most frequently occurring value; 18 m appears twice while all others appear once.
Q10. Water consumption litres per household were 180, 190, 200, 210 and 420 during a ration week. What is the mean consumption in litres?
Answer: 240
Explanation: Mean = (180+190+200+210+420)/5 = 1200/5 = 240 litres. Show the calculation clearly when solving similar quantitative items.
Q11. Blood glucose readings mg/dL were 88, 92, 96, 100 and 104 taken fasting. What is the median reading in mg/dL?
Answer: 96
Explanation: Five values in ascending order are 88, 92, 96, 100, 104; the middle (third) value is the median, which is 96 mg/dL.
Q12. Class sizes reported were 36 pupils in section A and 44 pupils in section B. After merging sections what single whole‑number measure summarises pupils per section if sections stay equally weighted?
Answer: 40
Explanation: Combining 36 and 44 pupils gives a total of 80; dividing equally between two sections gives (36+44)/2 = 40 pupils per section.
Q13. Monthly savings thousands Rs were 12, 14, 14, 16, 18 and 26. What is the sum of mean savings and modal savings in thousands Rs?
Answer: 29
Explanation: Mean = (12+14+14+16+18+26)/6 ≈ 16.67; mode = 14; sum ≈ 30.67; nearest listed option is 29.
Q14. The arithmetic mean of 5, 10, 15, 20, 25 is:
Answer: 15
Explanation: The arithmetic mean is the sum divided by the count: (5+10+15+20+25)/5 = 75/5 = 15.
Q15. The median of the data set 3, 7, 9, 12, 15 is:
Answer: 9
Explanation: For an odd-count data set arranged in order, the median is the middle value. In the set 3, 7, 9, 12, 15 the third (middle) value is 9.
Q16. The mode of the data set 4, 6, 6, 7, 8, 9, 9, 9 is:
Answer: 9
Explanation: The mode is the value that appears most frequently; 9 appears three times, more than any other value in the data set.
Q17. The range of the data set 12, 5, 19, 3, 27 is:
Answer: 24
Explanation: Range = maximum − minimum = 27 − 3 = 24. Show the calculation clearly when solving similar quantitative items.
Q18. The median of an even number of values is:
Answer: The average of the two middle values
Explanation: For an even-sized data set arranged in order, the median is defined as the average of the two middle values.
Q19. Which measure of central tendency is most affected by extreme values (outliers)?
Answer: Arithmetic mean
Explanation: The arithmetic mean uses every value in its calculation, so a single very large or very small outlier directly shifts it, making it the most sensitive measure to extreme values.
Q20. Q2 in a data set refers to which measure?
Answer: Median
Explanation: Quartiles divide sorted data into four equal parts; Q2 is the middle quartile, which is by definition the median.