Question

Engineers want to design seats in commercial aircraft so that they are wide enough to fit 99% of all males. (Accommodating 100% of males would require very wide seats that would be much too expensive.) Men have hip breadths that are normally distributed with a mean of 14.1 in. and a standard deviation of 0.8 in. Find P99. That is, find the hip breadth for men that separates the smallest 99% from the largest 1%. 

The hip breadth for men that separates the smallest 99% from the largest 1% is P99 = _______  in.

Answer 1

Given that

mean = = 14.1

standard deviation = = 0.8

Using standard normal table,

P(Z < z) = 99%

P(Z < 2.33) = 0.99

z = 2.33

Using z-score formula,

x = z * +

x = 2.33 * 0.8 + 14.1 = 15.964

P₉₉ = 15.9