. (Sec. 7.4) The amount of lateral expansion (mils) was determined for a sample of n = 10 pulsed-power gas metal arc welds used in LNG ship containment tanks. The resulting sample standard deviation was s = 2.81 mils. (a) Assuming normality, derive a 99% CI for σ 2 and for σ. (b) Assuming normality, derive a 99% upper confidence bound for σ 2 and for σ.