BMST Data Interpretation and Probability 4 — Questions and Answers
Question 1: A survey of 150 people found 90 own a car, 60 own a bicycle, and 30 own both. How many own neither?
- 30 (Correct answer)
- 20
- 40
- 50
Correct answer: 30
Using inclusion-exclusion: 90+60−30=120 own at least one; 150−120=30 own neither.
Question 2: A line graph shows a company's profit doubling each year from $10,000 in Year 1. What is the profit in Year 4?
- $80,000 (Correct answer)
- $40,000
- $60,000
- $100,000
Correct answer: $80,000
Year 2=$20,000; Year 3=$40,000; Year 4=$80,000 (doubling each year).
Question 3: The probability of event A is 0.4 and event B is 0.3. If A and B are mutually exclusive, what is P(A or B)?
- 0.7 (Correct answer)
- 0.12
- 0.58
- 1.0
Correct answer: 0.7
For mutually exclusive events, P(A or B) = P(A) + P(B) = 0.4 + 0.3 = 0.7.
Question 4: A stem-and-leaf plot shows stems 1, 2, 3 with leaves 2,5 | 1,4,8 | 0,3. What is the largest value?
- 33 (Correct answer)
- 38
- 30
- 35
Correct answer: 33
Stem 3 with leaf 3 gives 33, which is the largest value in the plot.
Question 5: A data set has a mean of 50 and standard deviation of 5. Approximately what percentage of data falls within one standard deviation of the mean?
- 68% (Correct answer)
- 95%
- 99.7%
- 50%
Correct answer: 68%
By the empirical rule, approximately 68% of data falls within one standard deviation of the mean.
Question 6: A jar contains 3 red, 5 blue, and 2 yellow candies. If one is drawn and not replaced, then another is drawn, what is the probability both are blue?
- 2/9 (Correct answer)
- 1/4
- 1/5
- 5/18
Correct answer: 2/9
P(blue then blue) = 5/10 × 4/9 = 20/90 = 2/9.
Question 7: A frequency table shows test scores: 60–69 (5 students), 70–79 (12 students), 80–89 (18 students), 90–99 (5 students). What is the modal class?
- 80–89 (Correct answer)
- 70–79
- 90–99
- 60–69
Correct answer: 80–89
The modal class is 80–89 because it has the highest frequency of 18 students.
BMST Data Interpretation and Probability 4
A survey of 150 people found 90 own a car, 60 own a bicycle, and 30 own both.
How many own neither?