PSSA PSSA Data Analysis and Statistics 2 — Questions and Answers
Question 1: A bag contains 4 red marbles, 3 blue marbles, and 5 green marbles. If one marble is drawn at random, what is the probability it is NOT green?
- 5/12
- 7/12 (Correct answer)
- 1/2
- 1/3
Correct answer: 7/12
There are 4 + 3 = 7 non-green marbles out of 12 total, so P(not green) = 7/12.
Question 2: The following data represents students' quiz scores: 70, 75, 80, 80, 85, 90, 95. What is the range?
- 15
- 20
- 25 (Correct answer)
- 30
Correct answer: 25
The range is the difference between the maximum and minimum values: 95 - 70 = 25.
Question 3: A pie chart shows that 25% of students chose math as their favorite subject. If 200 students were surveyed, how many chose math?
- 25
- 40
- 50 (Correct answer)
- 75
Correct answer: 50
25% of 200 = 0.25 × 200 = 50 students chose math as their favorite subject.
Question 4: Which measure of central tendency is MOST affected by an outlier (an extremely high or low value)?
- Mode
- Median
- Mean (Correct answer)
- Range
Correct answer: Mean
The mean is most affected by outliers because it includes all values in its calculation, pulling the average toward extreme values.
Question 5: A double bar graph compares boys' and girls' favorite sports. If 15 boys and 10 girls prefer swimming, what fraction of the total (25) prefer swimming?
- 1/5
- 2/5
- 3/5 (Correct answer)
- 4/5
Correct answer: 3/5
15 boys + 10 girls = 25 prefer swimming; 25/25 students in the swimming category means 3/5 of the boys prefer swimming (15/25 = 3/5).
Question 6: A frequency table shows: 1-10: 5 students, 11-20: 8 students, 21-30: 12 students, 31-40: 3 students. Which interval has the highest frequency?
- 1–10
- 11–20
- 21–30 (Correct answer)
- 31–40
Correct answer: 21–30
The interval 21–30 has 12 students, which is the highest frequency among all four intervals.
Question 7: If you flip a fair coin twice, what is the probability of getting heads both times?
- 1/4 (Correct answer)
- 1/2
- 3/4
- 1/3
Correct answer: 1/4
Each flip has a 1/2 probability of heads; for two independent events: 1/2 × 1/2 = 1/4.
PSSA PSSA Data Analysis and Statistics 2
A bag contains 4 red marbles, 3 blue marbles, and 5 green marbles.
If one marble is drawn at random, what is the probability it is NOT green?