ISAT Data Interpretation: Graphs/Tables 3 — Questions and Answers
Question 1: A frequency table shows the ages of 50 survey respondents: 18-24: 12, 25-34: 18, 35-44: 11, 45-54: 6, 55+: 3. What is the relative frequency of the 25-34 age group?
- 0.22
- 0.30
- 0.36 (Correct answer)
- 0.18
Correct answer: 0.36
Relative frequency = 18/50 = 0.36.
Question 2: A stacked bar chart shows the composition of a country's energy production (GWh) across three years. The chart shows that total production increased from 500 GWh in Year 1 to 650 GWh in Year 3. If renewable energy represented 20% in Year 1 and 35% in Year 3, how many more GWh of renewable energy were produced in Year 3 than Year 1?
- 127.5 GWh (Correct answer)
- 100 GWh
- 127.5 GWh
- 130 GWh
Correct answer: 127.5 GWh
Year 1 renewable = 20% × 500 = 100 GWh; Year 3 renewable = 35% × 650 = 227.5 GWh; difference = 127.5 GWh.
Question 3: A line graph tracks a company's quarterly revenue ($million): Q1=4.2, Q2=5.8, Q3=5.1, Q4=6.9. What was the average quarterly revenue for the year?
- $5.2M
- $5.5M (Correct answer)
- $5.8M
- $6.0M
Correct answer: $5.5M
Average = (4.2+5.8+5.1+6.9)/4 = 22.0/4 = $5.5M.
Question 4: A histogram displays the distribution of test scores for a class of 30 students in intervals of 10. The bars show: 50-59: 3, 60-69: 7, 70-79: 11, 80-89: 6, 90-99: 3. Which description best fits this distribution?
- Uniform distribution
- Skewed right (positively skewed)
- Approximately normal (bell-shaped) (Correct answer)
- Skewed left (negatively skewed)
Correct answer: Approximately normal (bell-shaped)
The distribution peaks in the middle interval (70-79) and tapers symmetrically on both sides, indicating an approximately normal bell-shaped distribution.
Question 5: A table shows the production costs and selling prices for three products. Product X: cost=$15, price=$24. Product Y: cost=$40, price=$58. Product Z: cost=$8, price=$14. Ranking by profit margin percentage from highest to lowest, which order is correct?
- X, Y, Z
- Z, X, Y (Correct answer)
- Y, X, Z
- X, Z, Y
Correct answer: Z, X, Y
Z margin = 6/8=75%, X margin = 9/15=60%, Y margin = 18/40=45%; so Z > X > Y.
Question 6: A graph shows population growth in three cities from 2010 to 2020. City A grew from 250,000 to 310,000. City B grew from 180,000 to 252,000. City C grew from 400,000 to 460,000. Which city had the highest percentage population growth?
- City A
- City B (Correct answer)
- City C
- All grew at the same rate
Correct answer: City B
City B grew by 72,000/180,000 = 40%, while City A grew 24% and City C grew 15%.
Question 7: A two-way table shows students who passed or failed two subjects. Math Pass/English Pass: 45. Math Pass/English Fail: 15. Math Fail/English Pass: 10. Math Fail/English Fail: 5. What fraction of students who passed Math also passed English?
- 3/4 (Correct answer)
- 9/15
- 3/5
- 9/12
Correct answer: 3/4
Students who passed Math = 45+15 = 60; those who also passed English = 45; fraction = 45/60 = 3/4.
ISAT Data Interpretation: Graphs/Tables 3
A frequency table shows the ages of 50 survey respondents: 18-24: 12, 25-34: 18, 35-44: 11, 45-54: 6, 55+: 3.
What is the relative frequency of the 25-34 age group?