2) A concrete manufacturer wants to implement \"quality control\" of the concrete mixture so that only 5% of the concrete has compressive strength below 30 MPa (for safety) and only 10% of the concrete has compressive strength above 36 MPa (for cost efciency). Assuming compressive strength is normally distributed, _$_Ii e 252 fX(-T) = 27m then what values of a and 0 will provide such control? Note that in practice, a is set by the ingredients used in the mixture (the design), while 0 is determined by the amount of care taken in selecting, measuring, and mixing the ingredients (quality control). That is, quality control is usually aimed at reducing o