Man I hate probability...anyhow could some help me with this Q as I am not understanding how to set it up... Suppose that the force acting on a column which helps to support a building is normally distributed with mean 15.0 kips and standard deviation 1.25 kips: What is the probability that the force differs from 15.0 kips by at most two standard deviations? Do they mean this inequality: 12.5<F<17.5, where the < means greater than or equal to and > less than equal to It just came to me by the way Oh i know i am suppose to standardize the raw variable I jus didnt bother as I wanted to know if this is how I go about setting up the prob. Also this one has stomped me as I dont know once again how to set this up. The distribution of time taken to read through once and answer questions on a multiple choice exam is known to be normal with mean 65 min and standard deviation 15.2 min. How long should the test last if the examiners want to ensure that 95% of all those taking the exams have at least 10 min to check back over their work after going through the exam once?