NCDAP Data Analysis & Statistics 2 — Questions and Answers
Question 1: A number cube (die) is rolled once. What is the probability of rolling a number greater than 4?
- 1/3 (Correct answer)
- 1/2
- 2/3
- 1/6
Correct answer: 1/3
Numbers greater than 4 on a standard die are 5 and 6, which is 2 out of 6 possible outcomes = 2/6 = 1/3.
Question 2: The following scores were recorded: 60, 75, 80, 80, 90, 95. What is the range?
- 35 (Correct answer)
- 25
- 80
- 30
Correct answer: 35
Range = maximum − minimum = 95 − 60 = 35.
Question 3: A line graph shows a company's sales increased from $20,000 in 2020 to $30,000 in 2022. What was the percent increase?
- 50% (Correct answer)
- 33%
- 25%
- 10%
Correct answer: 50%
Percent increase = (change ÷ original) × 100 = (10,000 ÷ 20,000) × 100 = 50%.
Question 4: Which measure of central tendency is MOST affected by an extreme outlier in a data set?
- Mean (Correct answer)
- Median
- Mode
- Range
Correct answer: Mean
The mean uses every value in its calculation, so one extreme outlier can significantly pull it up or down.
Question 5: A bag contains 4 red marbles, 3 blue marbles, and 3 green marbles. If one marble is drawn at random, what is the probability it is blue?
- 3/10 (Correct answer)
- 1/3
- 3/7
- 1/4
Correct answer: 3/10
There are 3 blue marbles out of 4+3+3=10 total marbles, so the probability is 3/10.
Question 6: The stem-and-leaf plot shows the values: 2|3 4 5, 3|1 6, 4|0 2. How many data values are there in total?
- 7 (Correct answer)
- 6
- 8
- 5
Correct answer: 7
Counting the leaves: 3 leaves in the 20s, 2 leaves in the 30s, and 2 leaves in the 40s = 7 total values.
Question 7: If the average of four numbers is 15, what is their sum?
- 60 (Correct answer)
- 45
- 30
- 75
Correct answer: 60
Sum = mean × count = 15 × 4 = 60.
NCDAP Data Analysis & Statistics 2
A number cube (die) is rolled once.
What is the probability of rolling a number greater than 4?