Hi, ... such that at least 90% of the cartons have more that 16 ounces of ice cream. What should be the mean amount of ice cream put into these cartons by this machine? Normal Distribution: σ = .18using z = -1.282, gives upper 10% (1.282)(.18) + 16 = μ = 16.23 (rounded to same decimal points as σ ) Wish You the Best in your Studies.