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.

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 a significance level of .01.
b. Estimate the difference between true average strengths for the two grades in a way that provides information about precision and reliability

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Sample Mean Size (k/mm SD Sample Sample Grade AISI 1064 AISI 1078 'n = 129 n 1 29 r-l07. s,=1.3 2 2.0 = 123.6