Line Plot (Dot Plot) Examples in Statistics

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

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

Concept Recap

A line plot (also called a dot plot) is a diagram that displays data values as marks — usually X's or dots — stacked above their corresponding values on a number line. Each mark represents one data point, making it easy to see the frequency of each value.

Imagine a number line where every time someone picks a number, you stack an X above it. Taller stacks mean more people chose that number. You can quickly see which values are popular.

Read the full concept explanation →

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 stacks marks above a number line to show frequency. The height of each stack reveals the most and least common values at a glance.

Common stuck point: Students sometimes skip values with zero occurrences, compressing the number line and making the distribution look different than it is.

Sense of Study hint: When making a line plot, first draw a number line covering the range of your data with evenly spaced values. Then go through each data point one at a time, placing an X (or dot) above its value. Finally, count the stacks to find the mode and look for clusters or gaps.

Worked Examples

Example 1

easy
Students measured the lengths of 10 leaves (in cm): 5, 6, 5, 7, 6, 5, 8, 6, 7, 5. Create a line plot (dot plot on a number line) for this data.

Solution

  1. 1
    Step 1: Draw a number line from 5 to 8.
  2. 2
    Step 2: For each data value, place an X (or dot) above the corresponding number: 5 appears 4 times, 6 appears 3 times, 7 appears 2 times, 8 appears 1 time.
  3. 3
    Step 3: Stack the X marks vertically. The result shows 4 X's above 5, 3 X's above 6, 2 X's above 7, and 1 X above 8.

Answer

Line plot with X marks: above 5: XXXX, above 6: XXX, above 7: XX, above 8: X.
A line plot (also called a dot plot) displays data along a number line, with one mark for each data value stacked vertically. It makes it easy to see the frequency of each value and the overall distribution shape at a glance.

Example 2

medium
A line plot shows the number of hours students spent on homework: 1 hour (2 dots), 1.5 hours (4 dots), 2 hours (5 dots), 2.5 hours (3 dots), 3 hours (1 dot). Find the total number of students and the total hours spent by all students combined.

Practice Problems

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

Example 1

medium
A line plot shows the weights of 12 apples in fractions of a pound: \frac{1}{4} (3 dots), \frac{1}{2} (5 dots), \frac{3}{4} (3 dots), 1 (1 dot). What is the mean weight of the apples?

Example 2

hard
Two classes made line plots of their test scores. Class A: 70 (1), 75 (3), 80 (6), 85 (4), 90 (1). Class B: 60 (2), 70 (3), 80 (5), 90 (3), 100 (2). Compare the centres and spreads of the two distributions.
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Related Concepts

Frequency Table

Background Knowledge

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

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