Question: The yield strength (ksi) for A36 steel is normally distributed with µ = 43 and σ = 4.5.
(a) What is the 25th percentile of the distribution of A36 steel strength?
(b) What strength value separates the strongest 10% from the others?
(c) What is the value of c such that the interval (43 - c, 43 + c) includes 99% of all strength values?
(d) What is the probability that at most three of 15 independently selected A36 steels have strength less than 43?