Practice Misleading Graphs in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A misleading graph is a data visualization that distorts the true pattern through truncated axes, unequal intervals, cherry-picked data, or manipulated scales.

A graph can tell any story the creator wants by choosing which data to show, where to start the axis, and how to scale the bars โ€” visual clarity requires honest design.

Showing a random 20 of 50 problems.

Example 1

challenge
Design a single honest bar chart, then list the THREE independent edits that would each separately make it misleading without changing any underlying value. Name them.

Example 2

medium
A school reports test scores per teacher but omits class sizes. Teacher A: mean 8080 from 44 students. Teacher B: mean 7878 from 4040 students. Why is a bar chart of just the means misleading?

Example 3

medium
A graph's bars are colored so the disliked option is bright red and the favored one is calm green, but axes are correct. Is this a data distortion?

Example 4

medium
A dual-axis chart plots revenue (left axis 00โ€“100100) and complaints (right axis 00โ€“1010) so the two lines cross. Why can this falsely suggest correlation?

Example 5

easy
A chart compares 'total crime' in two cities of very different population using raw counts. What is the flaw?

Example 6

medium
A truncated-axis chart shows bars at heights 2020 and 8080 pixels above baseline bb. The true values are 6060 and 120120. Find bb.

Example 7

medium
A dual-axis chart shows ice-cream sales (left axis, 00 to 100100) and shark attacks (right axis, 00 to 55) tracking each other. Does the visual correlation prove causation?

Example 8

easy
A pictogram doubles both the height AND width of an icon to show a value that doubled. What is wrong?

Example 9

easy
A graph claims 'unemployment doubled' going from 4.0%4.0\% to 4.1%4.1\%. What technique makes the claim feel dramatic?

Example 10

medium
A magazine shows incomes as stacked coins where coin stack height is proportional to income, but the coin diameter also grows with the stack. Income B is 3ร—3\times income A. What visual area ratio results if both width and height scale by 33?

Example 11

easy
A pie chart shows 30%30\%, 30%30\%, 40%40\%. The artist colors the 40%40\% slice in a dim gray and the two 30%30\% slices in bright yellow. Is the chart numerically misleading?

Example 12

easy
A line graph shows only the months where sales rose, omitting the months they fell. What technique is this?

Example 13

easy
A bar chart's y-axis starts at 9090 instead of 00. What visual effect does this create?

Example 14

hard
A pictogram shows three-dimensional spheres whose volumes are meant to represent the values 1,8,271, 8, 27. To be honest by volume, what is the ratio of the displayed radii?

Example 15

easy
Honest bar chart: Brand A sells 200200 units, Brand B sells 250250 units, y-axis starts at 00. By roughly what percent is B greater than A? And how does this look on the chart?

Example 16

hard
A chart claims 'support fell from 80%80\% to 76%76\% โ€” a major collapse.' The y-axis runs 75%75\% to 80%80\% and bars sit at heights 55 and 11. Compute the visual ratio, the true percentage-point drop, and the true relative drop.

Example 17

medium
A pictogram represents population by stick figures of height hh and width ww. To honestly show double the population using a figure twice as tall, what must the width do?

Example 18

challenge
A bar chart truncates its y-axis to start at value bb. Two bars have true values v1>v2>bv_1 > v_2 > b. Show that the ratio of drawn pixel heights is v1โˆ’bv2โˆ’b\frac{v_1-b}{v_2-b} and explain why choosing bb close to v2v_2 makes the exaggeration unbounded.

Example 19

medium
A graph shows 'cases of disease over time' with no y-axis label or values. The line goes up sharply. List three questions you should ask before drawing conclusions from this graph.

Example 20

medium
A pictogram doubles a square icon's side from 11 cm to 22 cm to represent a 2ร—2\times increase. Compute the area ratio and explain what the honest scaling would be.