Engineers must consider

Question

Engineers must consider the diameters of heads when designing helmets. The company researchers have determined that the population of potential clientele have head diameters that are normally distributed with a mean of 5.7-in and a standard deviation of 1.1-in. Due to financial constraints, the helmets will be designed to fit all men except those with head diameters that are in the smallest 1% or largest 1%.

What is the minimum head diameter that will fit the clientele?

min = 

What is the maximum head diameter that will fit the clientele?

max = 

Answer 1

Using a normal distribution table, read off the z valuee that has an area to the left of .99. The other solution is -z or the area is .01.

Because z = (x - μ)/σ you can solve for x = μ +/- zσ