10. An experiment was performed to compare the fracture toughness of high-purity 18 Ni maraging steel with commercial-purity steel of the same type (Corrosion Sci., 1971: 723—736). The sample average toughness was for m  32 specimens of the high-purity steel, whereas for n  38 specimens of commercial steel . Because the highpurity steel is more expensive, its use for a certain application can be justi ed only if its fracture toughness exceeds that of commercial-purity steel by more than 5. Suppose that both toughness distributions are normal.

a. Assuming that s1  1.2 and s2  1.1, test the relevant hypotheses using a  .001.

b. Compute b for the test conducted in part (a)

when m1  m2  6.