1. The problem statement, all variables and given/known data The diameter of a shaft in an optical storage drive is normally distributed N(μ,σ2). The drive specifies that the shaft be 0.2500 ± 0.0015 in. Suppose μ= 0.2508 in and σ = 0.0005 in. What fraction of shafts conform to the design specifications? 3. The attempt at a solution I am confused with the terminology of this problem. Is 0.2500 the population mean and 0.2508 is the sample mean? Or is this completely unrelated, and I have to find the probability that a length be between 0.2485 and 0.2515 in? Some help in getting started would be appreciated. Thank you!