Idea 8of 22Builds onAsk everyone, or ask some?
Whoever is nearby is not everyone
Why can asking whoever is nearby give the wrong answer?
Today you'll discover
- who a nearby sample shuts out
- why honest answers can still mislead
- a plan that reaches everyone
Think firstMaya asks at the basketball court
Maya asks 10 students at the basketball court. Will her answer match the whole school?
Decide first, then press Next. Look at who is outside the shaded box.
The same 60 students, with an orange box round the 12 at the basketball court in the top-left corner. Then a dashed shaded box marks the 12 who can be picked; the other 48 fade. Ten of the 12 are ringed. At the right, the sample's bar: 8 of 10 want a court; all 60 students: 18 of 60.
See the whole ideathe big idea and the key word, in one place
The big idea
A representative sample gives everyone a chance; asking only who is nearby shuts the rest out.
Same school, two answers
Maya's 10 at the court: 8 want a court. All 60 students: 18 want a court, only 3 in 10.
Other cornersThe hot-lunch line shuts out everyone who brings lunch. The bus line shuts out everyone who walks. The skate ramp shuts out everyone who reads.
Key word
- representative sample
- a sample that is like the whole population, because everyone had a chance to be picked
Ready to use it?
- Decide whether a plan can reach everyone in the population.