Definition
Line plot
A line plot places one mark for every data value above its position on a number line.
View exact chart data
| Length | Count |
|---|---|
| 1 | 1 |
| 1.5 | 2 |
| 2 | 3 |
| 2.5 | 1 |
| 3 | 0 |
What it means
Find each value on the number line and place one X or dot above it. If the same value appears again, stack another mark in the same column. That lets you read two things at once: where a value belongs and how often it occurs. Some elementary materials call this a dot plot.
Remember it
Position says the value; stack height says the frequency.
Example
For the measurements 1, 1½, 1½, 2, 2, 2, and 2½ centimetres, place one X above 1, two above 1½, three above 2, and one above 2½. The three-X stack shows that 2 centimetres occurs three times.
Watch for
A line plot is not a line graph: its marks are not joined to show change over time, and its number-line intervals must be equal.
Common mix-up
Count the marks above a tick, not the number of ticks on the scale.
Exact meaning
A line plot is a data display with a calibrated horizontal number line and one mark for each observation at its value. Marks for repeated values stack vertically, so horizontal position encodes the value and stack height encodes frequency.