Descriptive Statistics Flashcards
7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Descriptive Statistics flashcards as text
A two-way frequency table shows the counts for two categorical variables. What does a marginal frequency represent?
Answer: The total count for a single category across all groups
Marginal frequencies appear in the margins (row or column totals) and summarize one variable across all levels of the other.
A dataset with values 5, 5, 5, 5, 5 has a standard deviation of:
Answer: 0
When all values are identical, there is no spread, so the standard deviation is 0.
Which of the following is a measure of position rather than a measure of spread?
Answer: Percentile
Percentiles describe where a value stands relative to the rest of the data (position), not how spread out the data are.
A frequency histogram has bars of equal width. The area of each bar is proportional to:
Answer: The relative frequency of that class
With equal-width bars, bar area = width × height = constant × frequency, so area is proportional to relative frequency.
When comparing two boxplots, which feature most directly indicates that one distribution has greater variability?
Answer: A wider box (larger IQR)
The width of the box represents the IQR; a wider box signals greater spread in the middle 50% of the data.
What does it mean if the correlation r = 0 between two quantitative variables?
Answer: There is no linear association between the variables
r = 0 indicates no linear relationship, though a non-linear relationship may still exist.
A relative frequency table shows that 0.35 of students prefer math. In a class of 200 students, how many prefer math?
Answer: 70
0.35 × 200 = 70 students prefer math.