Consider a demand or load versus capacity or strength relation, z = r - s, where r denotes the capacity and s the demand. assume that capacity is described by a normal distribution with r  = 200, r = 40, and the demand is also described by a normal distribution with s = 100, s  = 30. a) what is the distribution of z? b) estimate the mean and standard deviation of z; c) calculate the reliability index  and probability of failure pf.

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.