Use Data to Test a Claim

Success criteria

• I support a claim with specific numbers from the data.
• I distinguish “supports” from “proves.”
• I name at least one limitation and critique a misleading representation.

Learn and explain

Suppose a paper-plane design flew past a target line in 9 of 12 trials. That is 75% of these trials. The result supports the claim “this design often passed the line in our test.” It does not prove that it always works, that it beats every design, or that wind had no effect.

Use this reasoning chain:

1. Claim: precise and answerable.
2. Evidence: numbers or observations that actually address it.
3. Reasoning: why those numbers matter.
4. Limitation: what the sample or method cannot establish.

Independent practice

Unfamiliar transfer — graph detective

Two products score 90 and 100. A graph starting at 90 uses its full plotting height for their 10-point difference; a graph starting at 0 uses only one tenth of that height for the same difference. The truncated axis therefore magnifies the visible difference by a factor of 10.

Collect or reuse one small authentic dataset. Make a graph by hand, write one supported claim, and name one limitation. Ask another person what they think the graph says; revise if their interpretation differs from yours.

Delayed check

One to two weeks later, inspect an unfamiliar graph from a newspaper, school notice, or advertisement. Record its source, claim, evidence, scale, and one question you would ask before believing it.

Evidence path

Save the final graph, raw data, supported claim, limitation, and revision note to jeremy/portfolio/math/unit-6/lesson-18-data-claim/.

Next step

• Repair: if claim and evidence do not match, narrow the claim until the numbers address it.
• Continue: if the critique is independent, complete the Unit 6 delayed check and year comparison.
• Stretch: calculate additional summaries only when they sharpen the claim; never use them as decoration.