Tensile-strength tests were carried out on two different grades of wire rod (“Fluidized Bed Patenting of Wire Rods,” Wire J., June 1977: 56–61), resulting in the accompanying data.

Sample Sample Mean Sample Grade Size (kg/mm2

) SD AISI 1064 AISI 1078

a. Does the data provide compelling evidence for concluding that true average strength for the 1078 grade exceeds that for the 1064 grade by more than 10 kg/mm2

? Test the appropriate hypotheses using the P-value approach.

b. Estimate the difference between true average strengths for the two grades in a way that provides information about precision and reliability.