Statistics · Challenge 22 of 25 · about 6 min
Which Class Varies More?
Compare aligned dot plots to see clustering and horizontal spread.
Year 4 challenge progress
0 of 25 complete
1 Read
Your challenge
Class A reading times are 14, 15, 15, 15 and 16 minutes. Class B reading times are 10, 13, 15, 17 and 20 minutes. Using a raw number table and two aligned dot plots on the same scale, which display makes variation easiest to see, and which class has greater variation?
Take your time. Your answer is checked only when you choose Check Answer.
Curriculum details
- Curriculum code
- VC2M4ST02
- Strand
- Statistics
- Focus
- Compare displays and identify clustering and variation.
2–5 Notice · Build · Move · Connect
Interactive visual
An interactive Look at the spread model is ready. Choose Show Visual Trick to reveal and hear one mathematical change at a time.
Visual Trick
Look at the spread
A wider horizontal spread shows greater variation, while stacked dots show a cluster.
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Step 1
Plot both classes on the same horizontal scale.
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Step 2
Draw a bracket from 14 to 16 for Class A.
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Step 3
Draw a bracket from 10 to 20 for Class B.
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Step 4
Compare the narrow Class A spread with the wide Class B spread.
6 Solve
Your answer
7 Check
Worked explanation
Why the answer makes sense
- Class A has range 16 − 14 = 2 and clusters around 15.
- Class B has range 20 − 10 = 10 and is more spread out.
- Aligned dot plots make the widths easiest to compare, and Class B has greater variation.
Challenge complete
This counts as one completed curriculum item. You can replay the model or review it again anytime.