Quartiles for Normal distributions. The quartiles of any distribution are the values with cumulative proportions 0.25 and 0.75.
(a) What are the quartiles of the standard Normal distribution?
(b) Using your numerical values from (a), write an equation that gives the quartiles of the N(μ,σ) distribution in terms of μ and σ.
(c) The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days. Apply your result from (b): what are the quartiles of the distribution of lengths of human pregnancies?