Beyond Common Core
Problem 39 of 45s12-039
Last year 20% of students biked to school. This year 27 of a random 100 do. Test vs at . Area left of : ; of : .
Try it first
The walkthrough opens once you check an answer.
Solution walkthrough2:10
- If is true, is roughly normal with mean and SD .
- The sample gives , so .
- says , so the p-value is the right tail: .
- Compare the p-value with : , so reject . More than 20% now bike.
- Traps: in the SE gives ; is the wrong tail; and is never compared with .