Core Academic Skills Assessment Mathematics: Data and Statistics 2 — Questions and Answers
Question 1: A dataset has values: 4, 7, 7, 9, 13, 15, 15, 15, 20. What is the mode?
- 7
- 9
- 13
- 15 (Correct answer)
Correct answer: 15
The mode is 15 because it appears three times, more than any other value.
Question 2: The box plot for a dataset shows Q1 = 12, median = 18, Q3 = 26. What is the interquartile range (IQR)?
- 6
- 8
- 14 (Correct answer)
- 18
Correct answer: 14
The IQR equals Q3 minus Q1, so 26 − 12 = 14.
Question 3: A survey finds 60% of students prefer math, 30% prefer reading, and 10% prefer science. In a class of 40 students, how many prefer reading?
- 4
- 10
- 12 (Correct answer)
- 24
Correct answer: 12
30% of 40 = 0.30 × 40 = 12 students prefer reading.
Question 4: Which measure of central tendency is MOST affected by an extreme outlier?
- Median
- Mode
- Mean (Correct answer)
- Range
Correct answer: Mean
The mean uses all values in its calculation, so an extreme outlier pulls it significantly away from the center.
Question 5: A scatter plot shows points clustered closely around a line going from lower-left to upper-right. This indicates:
- No correlation
- A strong negative correlation
- A strong positive correlation (Correct answer)
- A weak positive correlation
Correct answer: A strong positive correlation
Points clustered tightly along an upward-trending line indicate a strong positive correlation.
Question 6: Data set: 5, 8, 10, 12, 15. If the value 15 is replaced with 35, which measure changes the MOST?
- Median
- Mode
- Mean (Correct answer)
- Lower quartile
Correct answer: Mean
Replacing 15 with 35 adds 20 to the sum; the mean increases by 20/5 = 4, while the median stays at 10.
Question 7: A two-way table shows 80 students: 45 are girls, 35 are boys; 50 play sports and 30 do not. If 28 girls play sports, how many boys play sports?
- 17
- 22 (Correct answer)
- 28
- 30
Correct answer: 22
Total students who play sports is 50; if 28 are girls, then 50 − 28 = 22 boys play sports.
Core Academic Skills Assessment Mathematics: Data and Statistics 2
A dataset has values: 4, 7, 7, 9, 13, 15, 15, 15, 20.
What is the mode?