Line Plots Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Line Plots.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

A line plot (dot plot) displays data by placing marks (dots or Xs) above a number line to show the frequency of each value.

Like stacking coins above each number โ€” taller stacks mean that value appeared more often in the data.

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How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: A line plot piles dots or Xs above each value on a number line to show how often it appears.

Common stuck point: The procedure for line plots is the easy part; the trap is leaving out values with zero marks. Asking "Am I stacking a mark for each data point above its value on a number line to show frequency?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Am I stacking a mark for each data point above its value on a number line to show frequency?

Worked Examples

Example 1

medium
Plot: 4โ†’24\to 2, 5โ†’45\to 4, 6โ†’36\to 3, 7โ†’17\to 1. Find the median.

Answer

55

First step

1
Total dots =2+4+3+1=10= 2+4+3+1 = 10.

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Example 2

medium
A line plot shows lengths in 14\tfrac{1}{4}-inch units: 14โ†’2\tfrac{1}{4}\to 2, 24โ†’3\tfrac{2}{4}\to 3, 34โ†’1\tfrac{3}{4}\to 1. Find the total length.

Example 3

medium
A line plot of book pages read by 55 kids shows the mean is 2020. Four of the values are 10,15,20,2510, 15, 20, 25. What is the fifth?

Example 4

hard
Plot: values 1,2,3,41, 2, 3, 4 with frequencies 3,4,2,13, 4, 2, 1 and one more dot at unknown value vv. The total sum of the data is 2424. Find vv.

Example 5

hard
A line plot of weekly hours studied: 2โ†’12\to 1, 3โ†’23\to 2, 4โ†’44\to 4, 5โ†’25\to 2, 6โ†’16\to 1. If each value increases by 22 hours, what is the new mean?

Example 6

hard
Plot of lengths (in.): 12โ†’3\tfrac{1}{2}\to 3, 1โ†’21\to 2, 112โ†’41\tfrac{1}{2}\to 4, 2โ†’12\to 1. Find the total length.

Example 7

challenge
Two line plots have the same range [0,10][0, 10], same total count 2020, and same median 55. Plot A: 0โ†’100\to 10, 10โ†’1010\to 10. Plot B: all 2020 dots at 55. Which has greater spread, and what does this tell you about median alone as a summary?

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
A line plot has 4 dots above the value 3. How many data points equal 3?

Example 2

easy
True or false: a line plot connects its dots with line segments.

Example 3

easy
Dots: 2 above 5, 3 above 6, 1 above 7. How many data points total?

Example 4

easy
Which value is the mode: 1 dot above 4, 5 above 5, 2 above 6?

Example 5

easy
On a line plot, what does a taller stack of dots mean?

Example 6

easy
A line plot shows values 2,3,4,5. The range is?

Example 7

easy
Should a line plot show a value on the number line even if it has 0 dots?

Example 8

easy
If each dot is one student's pet count, what does a dot above 2 mean?

Example 9

medium
Dots: 5โ†’1, 6โ†’3, 7โ†’2, 8โ†’2. What is the total number of data points?

Example 10

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Data on a plot: 3,3,4,5,5,5. Find the median.

Example 11

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Plot: 2โ†’2, 3โ†’3, 4โ†’1. Find the mean.

Example 12

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A line plot of test scores has an obvious dot far right of the rest. What is it called?

Example 13

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Plot A is tightly clustered; Plot B is spread out, same center. Which has more variability?

Example 14

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How many dots are needed so a plot of 4,4,5,6 has a mean of 5 after adding one dot?

Example 15

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A line plot shows shoe sizes. Is shoe size categorical or numerical data?

Example 16

challenge
A line plot has values 1,2,31, 2, 3 with frequencies 1โ†’21 \to 2, 2โ†’a2 \to a, 3โ†’23 \to 2, for a total of 99 data points. What is the mean?

Example 17

challenge
Two line plots have the same range and median but look different. What feature must differ?

Example 18

challenge
A plot of 10 values has mean 6. If every value increases by 2, what is the new mean?

Example 19

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A line plot shows daily rainfall (mm): 0โ†’3, 1โ†’2, 2โ†’1. On how many days did it rain?

Example 20

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Plot: 10โ†’1, 20โ†’2, 30โ†’1. Find the mean.

Example 21

easy
A line plot shows 6 Xs above 22. How many data points equal 22?

Example 22

easy
A plot has dots at 11 (once), 22 (twice), 33 (three times). How many dots total?

Example 23

easy
On a line plot of pencil lengths (in.), there are 00 dots above 55 but dots at 44 and 66. Should you still show 55 on the number line?

Example 24

easy
A line plot shows ages: 77 appears 44 times. What is the frequency of age 77?

Example 25

easy
Dots: 0โ†’20\to 2, 1โ†’51\to 5, 2โ†’32\to 3. What value has the tallest stack?

Example 26

easy
A line plot's values go from 11 to 88. What is the range?

Example 27

easy
A line plot shows scores 90,92,95,95,9890, 92, 95, 95, 98. What is the mode?

Example 28

medium
Plot: 0โ†’10\to 1, 1โ†’21\to 2, 2โ†’22\to 2, 3โ†’53\to 5. Find the mean.

Example 29

medium
A line plot shows pet counts for 1212 kids. If 44 have 00 pets and 33 have 11 pet, how many have โ‰ฅ2\ge 2 pets?

Example 30

medium
Plot of plant heights (cm): 10โ†’210\to 2, 11โ†’311\to 3, 12โ†’412\to 4, 13โ†’113\to 1. What is the range?

Example 31

medium
A class line plot shows test scores. Out of 2020 students, 1414 scored โ‰ฅ80\ge 80. What percent is that?

Example 32

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Plot: 5โ†’15\to 1, 6โ†’26\to 2, 7โ†’37\to 3, 8โ†’28\to 2, 9โ†’29\to 2. Find the median.

Example 33

medium
Frequencies: 1โ†’31\to 3, 2โ†’42\to 4, 3โ†’33\to 3. Is the distribution symmetric?

Example 34

medium
A line plot of 88 values has range 66 and minimum 44. What is the maximum?

Example 35

hard
A line plot has values 2,4,6,82,4,6,8 with frequencies 1,3,3,11,3,3,1. What is the median?

Example 36

hard
A line plot of 77 data values has mode 44 and mean 55. What is the sum of the data?

Example 37

hard
A line plot of 99 values has median 77. If you add one more dot at 2020, what is the new median?

Example 38

hard
A line plot of test scores is skewed right (long tail to high values). Which is greater: mean or median?

Example 39

hard
A line plot of 1010 values has mean 66. If one 66 is replaced by 1616, what is the new mean?

Example 40

hard
On a line plot, 2020 kids reported siblings. Counts: 0โ†’50\to 5, 1โ†’81\to 8, 2โ†’42\to 4, 3โ†’33\to 3. What fraction have at least 22 siblings?

Background Knowledge

These ideas may be useful before you work through the harder examples.

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