Hi

*Note: 

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

 

RELATED QUESTIONS

Gestation Period           Mean Birth Weight               Standard Deviation
 
Under... (answered by stanbon)

what percent of the babies born with each gestation period have a low birth rate (under... (answered by stanbon)

a mean of 210.0 case of low birth weight each year.

1.  Find the mean number of low... (answered by robertb)

The gestation period (length of pregnancy) for male babies born in New York is normally... (answered by solver91311)

Figures from the Australian Bureau of Statistics and the Royal Alexandra Hospital
for... (answered by lynnlo)

birth weights in the united states have a distribution that is approximately normal with... (answered by Boreal)

The mean weight of newborn babies at a large maternity hospital is determined from random  (answered by Boreal)

The mean birth weight for Ethiopian babies is μ =3.1 kg with sd (σ=0.5 kg)
A) What... (answered by Boreal)

Birth weights are normally distributed with a mean of 3421g and a standard deviation of... (answered by ewatrrr)