Common Core: S-ID.4
Problem 8 of 45s12-008
A machine fills bags of rice with weights that are approximately normal, mean 500 g, SD 8 g. The 10th percentile has . What weight, in grams, is at the 10th percentile?
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Solution walkthrough1:43
- The 10th percentile is the weight with of bags below it, so it sits left of the mean.
- A -score counts SDs from the mean, so the value is .
- How far below the mean? SDs of g each: g.
- Below the mean, so subtract: g.
- Traps: drops the minus sign, forgets to multiply by the SD, and uses as .