Let’s assume that a private jet manufacturer in North America wants to design seats in its aircraft so they are wide enough to fit most men. Let’s further assume that the design engineers use anthropometric data from Fullenkamp et al. (2008), who reported that the sitting hip breadth for men is normally distributed with a mean of μ = 38.2 cm (15 in.) and a standard deviation of σ = 3.6 cm (1.4 in.).

(a) Determine the sitting hip breadth for men that would separate the smallest 75% from the largest 25%.

(b) Determine the sitting hip breadth for men that would separate the smallest 99% from the largest 1%.

(c) Do you think it would be “better” to design seats based on

(a) or

(b) and why?

(d) Why would it be necessary to make a distinction between the smallest and largest possible sitting hip breadths as in

(a) and (b). In other words, why not simply design seats to accommodate 100% of men?