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Convert both rejection rates into quantile equations

A grading machine rejects apples as too large if their mass exceeds 150 g, and too small if below 110 g. Over a long period 10% are too large and 15% too small. Apple mass in grams may be modelled by N(μ,σ2)N(\mu,\sigma^2). Find μ and σ.

[2005/Specimen Paper/II/9(modified)]

CJC · Discussion · Question 4

A10% upper tail is the 90 th percentile, not the 10 th.

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