Question 376225
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Hi
*Note: {{{z = blue(x - mu)/blue(sigma)}}}
P = .90 then z = NORMSINV(0.9) = 1.28

1.28 = ( x - 7.31) / 1.09
1.28*1.09 = x - 7.31
1.40 + 7.31 = x
8.71 lbs = x
the weight of the top 10% of the babies born > 8.71 lbs

1.28 = ( x - 7.61) / 1.11
1.28*1.11 = ( x - 7.61)
1.42 + 7.61 = 9.03 lbs = x
the weight of the top 10% of the babies born > 9.03 lbs