Some people use this rule to work out how many hours' sleep each night
young children need.
tract the child's age in years from 30,
ten divide the result by 2
Sanjay is 8 years old.
Use the rule to work out how many
hours' sleep he needs.

Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 25002500 grams and a standard deviation of 800800 grams while babies born after a gestation period of 40 weeks have a mean weight of 27002700 grams and a standard deviation of 385385 grams. if a 3232-week gestation period baby weighs 21252125 grams and a 4040-week gestation period baby weighs 23252325 grams, find the corresponding z-scores. which baby weighs lessless relative to the gestation period?