Algebra 1 / Unit 10: Data and Statistics
10.2 Dot Plots, Histograms and Box Plots
Notes
- A dot plot shows each value as a dot above a number line.
- A histogram groups data into equal-width bins and shows how many values fall in each.
- A box plot shows the five-number summary: minimum, $Q_1$, median, $Q_3$, maximum. The box covers the middle $50\%$.
- Shape: symmetric, skewed right (long tail to the right) or skewed left (long tail to the left).
Practice
In a box plot, what fraction of the data lies inside the box?
From $Q_1$ to $Q_3$ is the middle half.
A box plot has minimum 2, $Q_1$ = 5, median 8, $Q_3$ = 12, maximum 20. The IQR is:
$12 - 5 = 7$.
A histogram has most values on the left and a long tail stretching right. It is:
Skew is named for the direction of the tail.
Ready for more? Take the Unit 10 test.