NJSLA NJSLA Data Analysis and Statistics 2 — Questions and Answers
Question 1: A data set has values: 4, 4, 6, 8, 10, 10, 14. What is the mode?
- 4 and 10 (Correct answer)
- 4
- 10
- 8
Correct answer: 4 and 10
Both 4 and 10 appear twice, making this a bimodal data set with modes of 4 and 10.
Question 2: A probability experiment involves rolling a fair six-sided die. 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 die are 5 and 6, giving 2 favorable outcomes out of 6 total, which simplifies to 1/3.
Question 3: A line graph shows sales rising from January to June and falling from June to December. What does the peak in June represent?
- The maximum sales for the year (Correct answer)
- The minimum sales for the year
- The average monthly sales
- The median of all data points
Correct answer: The maximum sales for the year
The highest point on the line graph in June represents the maximum (peak) value of sales during that year.
Question 4: In a class of 30 students, 18 play sports. What is the ratio of students who play sports to those who do not?
- 3:2 (Correct answer)
- 2:3
- 3:5
- 5:3
Correct answer: 3:2
18 play sports and 12 do not; the ratio 18:12 simplifies to 3:2.
Question 5: Which statistic describes how spread out the values in a data set are from the mean?
- Standard deviation (Correct answer)
- Median
- Mode
- Range
Correct answer: Standard deviation
Standard deviation measures the average distance of each data point from the mean, quantifying how spread out the data is.
Question 6: A two-way frequency table shows data for 100 students categorized by grade level and sport preference. How is a joint frequency different from a marginal frequency?
- A joint frequency counts a specific combination of two categories, while a marginal frequency totals one entire row or column. (Correct answer)
- A joint frequency is the grand total, while a marginal frequency is a cell value.
- A joint frequency is always larger than a marginal frequency.
- A marginal frequency appears in the interior cells of the table.
Correct answer: A joint frequency counts a specific combination of two categories, while a marginal frequency totals one entire row or column.
Joint frequencies appear in the interior cells and represent two-category intersections, while marginal frequencies are the row or column totals.
NJSLA NJSLA Data Analysis and Statistics 2
A data set has values: 4, 4, 6, 8, 10, 10, 14.
What is the mode?