Beyond Common Core
Problem 43 of 45s12-043
A tulip mix is sold as 50% red, 30% yellow, 20% white. A sample of 200 bulbs has 82 red, 66 yellow, 52 white. At the critical values are 5.991 (df 2) and 7.815 (df 3). Which is correct?
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Solution walkthrough2:08
- If the claim is true, expect red, yellow and white.
- Find each gap and square it: , , .
- Divide each square by its expected count and add: .
- df , so use 5.991. Since , reject the claimed mix of colors.
- Traps: dividing by gives , not squaring gives , and df uses the wrong critical value.