NJSLA NJSLA Data Analysis and Statistics 1 — Questions and Answers
Question 1: A student recorded the following test scores: 72, 85, 90, 68, 95, 80. What is the median score?
- 82.5 (Correct answer)
- 80
- 85
- 83
Correct answer: 82.5
When the six scores are ordered (68, 72, 80, 85, 90, 95), the median is the average of the 3rd and 4th values: (80 + 85) / 2 = 82.5.
Question 2: Which measure of central tendency is most affected by an outlier?
- Mean (Correct answer)
- Median
- Mode
- Range
Correct answer: Mean
The mean is most affected by outliers because it sums all values and divides by the count, so an extreme value shifts it significantly.
Question 3: A box plot shows a minimum of 10, Q1 of 20, median of 35, Q3 of 50, and maximum of 70. What is the interquartile range (IQR)?
- 30 (Correct answer)
- 60
- 25
- 35
Correct answer: 30
The IQR equals Q3 minus Q1, so 50 − 20 = 30.
Question 4: A scatter plot shows points trending upward from left to right. This indicates which type of correlation?
- Positive correlation (Correct answer)
- Negative correlation
- No correlation
- Inverse correlation
Correct answer: Positive correlation
When both variables increase together and the points trend upward, the data shows a positive correlation.
Question 5: A survey of 200 students found that 60 prefer math. What percentage prefer math?
- 30% (Correct answer)
- 25%
- 35%
- 40%
Correct answer: 30%
60 divided by 200 equals 0.30, which is 30%.
Question 6: Which display is best for showing the distribution of a single set of numerical data?
- Histogram (Correct answer)
- Pie chart
- Bar graph
- Line graph
Correct answer: Histogram
A histogram groups numerical data into intervals and shows the frequency of each interval, making it ideal for displaying distribution.
NJSLA NJSLA Data Analysis and Statistics 1
A student recorded the following test scores: 72, 85, 90, 68, 95, 80.
What is the median score?