ERB 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 chosen at random, what is the probability of selecting a blue marble?
- 1/4
- 3/12 (Correct answer)
- 1/3
- 3/4
Correct answer: 3/12
There are 3 blue marbles out of 12 total (4+3+5=12), so the probability is 3/12, which simplifies to 1/4 but the exact fraction 3/12 is also listed.
Question 2: A frequency table shows that in a class, 6 students scored 60–69, 10 scored 70–79, 8 scored 80–89, and 4 scored 90–99. How many students are in the class?
- 24
- 28 (Correct answer)
- 26
- 30
Correct answer: 28
Total students = 6 + 10 + 8 + 4 = 28 students.
Question 3: A scatter plot shows data points generally moving from the lower-left to the upper-right of the graph. What type of correlation does this represent?
- Negative correlation
- No correlation
- Positive correlation (Correct answer)
- Inverse correlation
Correct answer: Positive correlation
When data points trend from lower-left to upper-right, as one variable increases the other also increases, indicating positive correlation.
Question 4: The high temperatures for one week were: 72, 75, 68, 74, 70, 85, 71. Which value is most likely an outlier?
- 72
- 70
- 85 (Correct answer)
- 74
Correct answer: 85
85°F is significantly higher than the other values (which cluster between 68–75), making it an outlier.
Question 5: A pie chart shows how a student spends 24 hours: Sleep 33%, School 29%, Homework 17%, Free Time 13%, Other 8%. How many hours does the student spend on homework?
- 4 hours
- 3 hours
- 4.08 hours (Correct answer)
- 5 hours
Correct answer: 4.08 hours
17% of 24 hours = 0.17 × 24 = 4.08 hours spent on homework.
Question 6: Two data sets have the same mean of 50. Set A has a range of 10, and Set B has a range of 60. What can you conclude?
- Set B has more data points than Set A
- Set A's data is more spread out than Set B's
- Set B's data is more spread out than Set A's (Correct answer)
- Both sets have the same distribution
Correct answer: Set B's data is more spread out than Set A's
A larger range indicates greater spread; Set B's range of 60 means its data values are more spread out than Set A's range of 10.
Question 7: A table shows that a plant grew 2 cm in Week 1, 4 cm in Week 2, 6 cm in Week 3, and 8 cm in Week 4. If the pattern continues, how much will the plant grow in Week 6?
- 10 cm
- 12 cm (Correct answer)
- 14 cm
- 16 cm
Correct answer: 12 cm
The plant grows 2 more centimeters each week; Week 5 = 10 cm, Week 6 = 12 cm.
ERB Data Analysis and Statistics 2
A bag contains 4 red marbles, 3 blue marbles, and 5 green marbles.
If one marble is chosen at random, what is the probability of selecting a blue marble?