1.) In Norway, the distribution of birth weights for infants whose gestational age is 40 weeks is approximately normal with mean Jl = 3500 grams and standard deviation u = 430 grams [7].

(a) Given a newborn whose gestational age is 40 weeks, what is the probability that his or her birth weight is less than 2500 grams?

(b) What value cuts off the lower 5% of the distribution of birth weights?

(c) Describe the distribution of means of samples of size 5 drawn from this population. List three properties.

(d) What value cuts off the lower 5% of the distribution of samples of size 5?

2.) For the population of females between the ages of 3 and 74 who participated in the National Health Interview Survey, the distribution of hemoglobin levels has mean Jl = 13.3 g/100 ml and standard deviation a= 1.12 g/100 ml [8].

(a) If repeated samples of size 15 are selected from this population, what proportion of the samples will have a mean hemoglobin level between 13.0 and 13.6 g/100 ml?

(b) If the repeated samples are of size 30, what proportion will have a mean between 13.0 and 13.6 g/100 ml?

(c) How large must the samples be for 95% of their means to lie within ::!::0.2 g/ 100 ml of the population mean Jl? (d) How large must the samples be for 95% of their means to lie within ::!::0.1 g/ 100 ml of the population mean?