Lesson 7.1 · Data
Line plots
You measured lots of things in the last unit. Now what? A line plot puts all your measurements on one number line, so you can see them at a glance.
What a line plot is
Definition
Line plot
A line plot is a number line with an ✕ above it for each measurement. Each ✕ stands for 1 thing.
The numbers go along the bottom. The ✕ marks stack up above each number. A tall stack means many things had that length.
Worked example: Read a line plot
Kim measured her pencils in inches. Each ✕ is one pencil.
- How many pencils are 5 inches long? Count the ✕ above 5. There are 3.
- How many pencils in all? Count every ✕: . There are 7 pencils.
- How many are longer than 5 inches? Look at 6 and 7: pencils.
Make a line plot
- Draw a number line. Start at the shortest length and end at the longest.
- Take one measurement at a time. Put an ✕ above its number.
- Cross it off your list so you don't count it twice.
Worked example: Make a line plot
Sam measured 7 leaves. Here are the lengths in inches:
3, 5, 4, 5, 6, 5, 3
The shortest is 3 and the longest is 6, so the line goes from 3 to 6. Put one ✕ for each leaf.
Check: ✕ marks for 7 leaves.
Worked example: Compare lengths
Use Sam's line plot. How much longer is the longest leaf than the shortest leaf?
The longest leaf is 6 inches. The shortest is 3 inches.
. The longest leaf is 3 inches longer.
Common mistake
Count the ✕ marks, not the numbers on the line. The number tells you the length. The ✕ marks tell you how many.
Tip
If a number has no ✕ above it, then 0 things had that length.
Practice
Use this line plot for Problems 1–4. It shows the lengths of toy cars in inches.
How many toy cars are 3 inches long?
Type a number.
How many toy cars are there in all?
Type a number.
Which length has the most toy cars?
How many toy cars are shorter than 4 inches?
Type a number.
Lily measured her crayons in inches:
4, 3, 4, 5, 4, 3
She makes a line plot. How many ✕ marks go above 4?
Type a number.
Use Lily's crayons from the last problem: 4, 3, 4, 5, 4, 3 inches. How many inches longer is her longest crayon than her shortest crayon?
Type a number.
This line plot shows the heights of plants in inches. How many plants are 6 inches tall?
Type a number.
This line plot shows the lengths of shells in centimeters. How many more shells are 7 cm long than 6 cm long?
Type a number.