Is this sample fair?, step by step
A statistic is a claim about a whole group made from a handful of it.
The question
A random 5% of all the year's orders are pulled and checked. Can this sample speak for the whole group?
Ask who could never have been asked
who is missing?
nobody missing
Yes — it is random
- A random 5% of all the year's orders are pulled and checked. A sample is only worth anything if it could have been anybody, so the question is not who WAS asked — it is who could not be.
- Nobody. Everyone in the group was in the draw and nothing about a person changed their chance of being picked. So the sample can stand for the whole group.
- Drawn from ALL the orders, so no kind of order is more likely.
How it works.
- 01
A random 5% of all the year's orders are pulled and checked. A sample is only worth anything if it could have been anybody, so the question is not who WAS asked — it is who could not be.
- 02
Nobody. Everyone in the group was in the draw and nothing about a person changed their chance of being picked. So the sample can stand for the whole group.
- 03
Drawn from ALL the orders, so no kind of order is more likely.