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Unformatted text preview: I 1078 n
123.6 Ha: Y - X > 10
. The p-value is essentially zero, so at any level of s
2.0 significance, we reject H0. The data overwhelmingly suggest that the mean tensile strength of the 1078 grade exceeds
the mean of the 1064 grade by more than 10 kg/mm .
b. A 95% confidence interval for Y - X will provide information on precision and reliability. The confidence interval is given
by . W e are 95% confident that the mean tensile strength of all 1078 gra de wire rods exceeds the mean tensile strength of the 1064 grade
wire rods by 15.59 to 16.41 kg/mm . 10. The data is summarized in the table.
a. The hypotheses are
H0: 1 - 2 = 5
The test statistic is versus Steel
2=Commercial Ha: 1 - 2 > 5
. The p-value is n
59.8 P(2.89 < Z) = 1 - .9981 = .0019. At the = .001 level of significance, we retain H0. The data do not provide sufficient
evidence at the 0.1% level of significance that the mean toughness of the high purity steel exceeds the mean for the
commercial grade by more than 5.
b. 13. If we set = mean deflection for the steel beams and = mean deflection for the beams made wi...
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- Spring '04
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