CLAST Statistics and Probability 2 — Questions and Answers
Question 1: A data set has values: 4, 7, 7, 9, 13. What is the mode?
- 4
- 7 (Correct answer)
- 9
- 13
Correct answer: 7
The mode is the value that appears most frequently, which is 7 (appears twice).
Question 2: If the probability of rain on any given day is 0.3, what is the probability that it does NOT rain?
- 0.3
- 0.7 (Correct answer)
- 0.6
- 0.4
Correct answer: 0.7
The complement rule states P(not A) = 1 − P(A), so 1 − 0.3 = 0.7.
Question 3: A bar graph shows sales of 40 in January, 55 in February, and 35 in March. What is the mean monthly sales?
- 40
- 43.3 (Correct answer)
- 45
- 55
Correct answer: 43.3
Mean = (40 + 55 + 35) / 3 = 130 / 3 ≈ 43.3.
Question 4: Which measure of central tendency is most affected by an extreme outlier?
- Mode
- Median
- Mean (Correct answer)
- Range
Correct answer: Mean
The mean is calculated using all values, so a single extreme outlier can significantly shift it.
Question 5: A bag contains 5 red, 3 blue, and 2 green marbles. If one marble is drawn at random, what is the probability it is blue?
- 1/3
- 3/10 (Correct answer)
- 3/5
- 1/5
Correct answer: 3/10
P(blue) = 3 / (5+3+2) = 3/10.
Question 6: The scores on a test are 60, 72, 85, 85, 90, 95. What is the median?
- 85 (Correct answer)
- 87.5
- 82.5
- 80
Correct answer: 85
With 6 values, the median is the average of the 3rd and 4th values: (85 + 85) / 2 = 85.
Question 7: A spinner has 8 equal sections numbered 1–8. What is the probability of spinning a number greater than 5?
- 3/8 (Correct answer)
- 5/8
- 1/2
- 1/4
Correct answer: 3/8
Numbers greater than 5 are 6, 7, and 8 — that is 3 out of 8 sections, so P = 3/8.
CLAST Statistics and Probability 2
A data set has values: 4, 7, 7, 9, 13.
What is the mode?