# Standard Deviation

• December 6th 2009, 01:46 PM
cechmanek32
Standard Deviation
Thank you for the two posters that helped me with my last question. I am really struggling with stats and have another question I really need help with:

Birth weights are normally distributed with a mean of 3419g and a standard deviation of 496g. If a hospital plans on setting up special observation conditions for the lightest 3% of babies, what weight is used for the cutoff separating the lightest 3% from the others?

I think this has to do with standard deviation and looking up .03 on my z-tables? If so, what happens next? Thank you so much for helping me, I'm so confused.
• December 6th 2009, 01:54 PM
pickslides
You need to find $x$ for $P\left(Z<\frac{x-3419}{496}\right)=0.03$