AP Stats Data Visualization and Interpretation 2 — Questions and Answers
Question 1: A back-to-back stemplot compares the test scores of two classes. Class A has a median of 82 and Class B has a median of 75. Which conclusion is best supported?
- Class A students are more consistent than Class B students.
- Typical scores in Class A are higher than in Class B. (Correct answer)
- Class A has a larger range than Class B.
- Class B has more outliers than Class A.
Correct answer: Typical scores in Class A are higher than in Class B.
The median represents the typical (middle) value, so Class A's higher median indicates its typical scores are higher.
Question 2: A cumulative relative frequency plot (ogive) shows that the 60th percentile corresponds to a value of 45. What does this mean?
- 45% of the data values are below 60.
- 60% of the data values are at or below 45. (Correct answer)
- The median is 45.
- 45 is the 40th percentile.
Correct answer: 60% of the data values are at or below 45.
The 60th percentile means 60% of data values fall at or below that value (45).
Question 3: Which graphical display is MOST useful for identifying whether a quantitative variable follows a roughly normal distribution?
- Bar chart
- Pie chart
- Histogram or dotplot (Correct answer)
- Scatterplot
Correct answer: Histogram or dotplot
Histograms and dotplots show the shape of a distribution, making it easy to assess symmetry and bell shape.
Question 4: A time series plot of monthly sales shows an overall upward trend with a repeating seasonal dip every December. This pattern is best described as:
- Random variation with no identifiable pattern.
- A trend with seasonal variation. (Correct answer)
- A perfectly linear relationship.
- Cyclical variation with no trend.
Correct answer: A trend with seasonal variation.
An overall directional movement (trend) combined with a repeating pattern within each year is called trend with seasonal variation.
Question 5: In a dotplot of 30 values, a single dot appears far to the right, separated from the main cluster. This point is most likely:
- The mean of the distribution.
- A potential outlier. (Correct answer)
- The median of the distribution.
- Evidence of a bimodal distribution.
Correct answer: A potential outlier.
A point separated from the main cluster of data is characteristic of an outlier.
Question 6: A boxplot shows Q1 = 20, median = 30, Q3 = 50, with a minimum of 10 and maximum of 70. Which statement about the distribution is correct?
- The distribution is symmetric.
- The upper half of the data is more spread out than the lower half. (Correct answer)
- The IQR is 20.
- The range is 40.
Correct answer: The upper half of the data is more spread out than the lower half.
The upper half spans Q3 to max = 20 units, while the lower half spans min to Q1 = 10 units, indicating more spread in the upper half.
Question 7: A two-way frequency table shows the relationship between gender (male/female) and preferred social media platform. To compare platform preferences between genders, you should use:
- Joint frequencies from the table.
- Row or column conditional relative frequencies. (Correct answer)
- Marginal totals only.
- A scatterplot of the two variables.
Correct answer: Row or column conditional relative frequencies.
Conditional relative frequencies (row % or column %) allow fair comparison between groups of different sizes.
AP Stats Data Visualization and Interpretation 2
A back-to-back stemplot compares the test scores of two classes.
Class A has a median of 82 and Class B has a median of 75.
Which conclusion is best supported?