Find the column the result follows
- The idea
- Predict
- See it
- Why
- Check
The idea
“I can compare the rows by whichever column sounds most important.”
A bigger population sounds like it has to matter. When several columns change at once, it's easy to grab that one without checking it.
The short version
The mistake: I can compare the rows by whichever column sounds most important.
What's actually true: Use the column the result rises and falls with. Check each one against the outcome first.
- To test a column, sort the rows by it. If the result climbs or falls in the same order, the column fits. If it jumps around, it can't explain the result.
- A blight kills plants that lack resistance. A population with more genetic variation is more likely to include plants that resist it.
- Big populations often hold more variation, but not always. A grass that spreads by cloning can grow thousands of near-identical plants.
On the exam: Before you compare by a column, check that the result rises and falls with it, row by row.