Skill: Interpret line plots

A line plot uses a number line to show data. Each $\times$ mark stands for one observation.

Look at this line plot. It shows the number of books four children read.

Number of books
        ×
    ×   ×       ×
×   ×   ×       ×
--------------------
1   2   3   4

Step 1: Count the marks above each number

• Above $1$: $1$ mark, so $1$ child read $1$ book.
• Above $2$: $3$ marks, so $3$ children read $2$ books.
• Above $3$: $1$ mark, so $1$ child read $3$ books.
• Above $4$: $2$ marks, so $2$ children read $4$ books.

Step 2: Find the most common value

The tallest stack is above $2$. Therefore, $2$ books was the most common number.

Step 3: Compare two values

There are $3$ marks above $2$ and $2$ marks above $4$.

$$3-2=1$$

So, 1 more child read 2 books than read 4 books.

Remember: Count each mark as one observation, then compare the numbers of marks.