Consider babies born in the “normal range” of 37–43 weeks gestational age. Extensive data…

 Consider babies born in the “normal range” of 37–43 weeks gestational age. Extensive data supports the assumption that for such babies born in the United States, birth weight is normally distributed with   3432 g and  482 g. [The article “Are Babies Normal?” (The American Statistician, 1999: 298–302) analyzed data from a particular year; for a sensible choice of class intervals, a histogram did not look normal but further investigation revealed that this was because some hospitals measured weight in grams and others measured to the nearest ounce and then converted the data to grams. A modified choice of class intervals that allowed for this gave a histogram that was well described by a normal distribution.]

a. For babies of this type, what proportion of all birth weights exceeds 4000 g?

b. For babies of this type, what proportion of all birth weights is between 3000 and 4000 g?

c. How would you characterize the highest .1% of all birth weights?

d. What value c is such that the interval (3432 2 c, 3432 1 c) includes 98% of all birth weights?