The variation in population of heights of pillars can be modeled as the normal distribution with mean 306.6 nm and standard deviation 37.0 nm.
i) For the pillar selected at random, what is the probability that its height is greater than 350 nm.
ii) According to normal model, what proportion of all existing pillars has heights greater than 350 nm? Describe your answer
iii) What proportions of pillars has heights between 270 nm and 350 nm?