SOLUTION: The mean weight of newborn babies at a large maternity hospital is determined from random sample of 65 babies. The mean weight is determined to be 3060g, with a standard deviation

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Question 972845: The mean weight of newborn babies at a large maternity hospital is determined from random sample of 65 babies. The mean weight is determined to be 3060g, with a standard deviation of 90g. What is the 99% confidence interval of this mean birth weight (to the nearest whole number)?
Thanks,
SM

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
xbar=3060
s=90
n=65
s/sqrt(n)=90/(sqrt(65)); the standard error is 11.16
confidence interval is z+/- SE; but z.99=2.58
2.58*11.16=28.80;;this is the half width of the 99% CI
(3031 gm, 3089 gm)