What is the probability that if an individual man is randomly selected, his hip breadth will be greater than 16.9 in?

Question

Suppose that an airline uses a seat width of 16.9 in. Assume men have hip breadths that are normally distributed with a mean of 14.5 in. and a standard deviation of 1 in. Complete parts​ (a) through​ (c) below.

Answer 1

Since it says that the distribution is "normal," we can calculate a z-score. z = (16.9 - 14.5)/1 = 2.4. The problem is asking about a hip breadth GREATER than 16.9 so we want to find the probability of a z-score GREATER than 2.4. By using a z-table or the normalcdf function on a TI calculator, p(z > 2.4) = 0.0082. We will leave our answer like that since that's how most statistical probability is done, although 0.82% is also an acceptable answer. There is no "rounding rule." There is only good rounding and bad rounding.