SAT Math: Interpreting Box Plots
18+ practice questions in Praczo
The concept, explained
- 1
A box plot (box-and-whisker plot) displays the 5-number summary: minimum, Q1 (25th percentile), median (50th percentile), Q3 (75th percentile), and maximum.
- 2
The "box" represents the interquartile range (IQR = Q3 - Q1), which contains the middle 50% of the data.
- 3
The line inside the box is the median. It does NOT represent the mean.
- 4
The "whiskers" extend to the minimum and maximum values (excluding outliers, which are sometimes shown as isolated dots).
- 5
You cannot determine the exact number of data points or the mean from a standard box plot.
- ✗ Confusing the median line inside the box with the mean of the data.
- ✗ Assuming the length of a quartile (e.g., Q1 to Median) implies more data points. Each quartile contains exactly 25% of the data; a longer section just means the data is more spread out there.
SAT-style practice
A box plot shows a median of 45, Q1 of 30, and Q3 of 55. What percentage of the data falls between 30 and 55?
Ready to master this concept?
Praczo tracks your mastery on all 179 SAT concepts — not just broad topics. One sample question is a start; drilling to mastery is how scores move.
3-day free trial — no credit card required